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OCM II

PROCESS MEASUREMENTS

OPEN CHANNEL MONITOR

Instruction Manual

PL-269

February 1991

33452690

hank you for purchasing Milltronics’ products.

We are committed to satisfying our customers’ needs with innovativeequipment that is designed for reliability and ease of use.

Milltronics has been designing and manufacturing process equipment since1954. Our fields of expertise include ultrasonic and capacitance levelmeasurement in-line weighing of dry bulk solids and motion sensing.

Milltronics is established world wide through associate offices andrepresentatives. Our network is continually being refined to provide ourcustomers with first rate sales information, engineering assistance and aftersales support.

For more details on our products and service, please contact us and we willprovide you with a listing of the offices or representatives nearest you.

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TABLE OF CONTENTS

SECTION TITLE PAGE

USERS GUIDE TO MANUAL iii

I GENERAL INFORMATION 1 - 1

II SPECIFICATIONS 2 - 1

III INSTALLATION

OCM II 3 - 1Battery 3 - 1Transducer 3 - 1Temperature Sensor 3 - 2Velocity Sensor 3 - 2Interconnection 3 - 2

IV START UP

General 4 - 1Keypad 4 - 2Keypad Entry 4 - 3Display 4 - 4Initial Start up 4 - 4P4 and F12 Auto Zero 4 - 6Setting the Clock 4 - 7Setting the Calendar 4 - 7

V DAILY OPERATION

Normal Operation, F2 5 - 1Flowrate Log, F9 5 - 2Daily Flow Total, F10 5 - 2

VI AUXILIARY OPERATIONS

F1 Emulation Mode 6 - 1F3 Clearing Totalizers 6 - 1F11 Clearing the Log Buffers 6 - 2F13 Diagnostic routine 6 - 2F14 Forced Cold Start 6 - 2Re-calibration 6 - 3

VII TABLES

#1 "D", displays 7 - 1#2 "F", functions 7 - 3#3 "P", parameters 7 - 5#4 "U", parameters 7 - 9

VIII MAINTENANCE 8 - 1

PL-269 10 – 1

IX APPENDICES

A ERROR CODES 9 - 1

B EXAMPLES #1 Parshall Flume 9 - 2 #2 Rectangular Flume 9 - 3 #3 Velocity-Area Product 9 - 4 Universal Head vs Flow Calculation 9 - 6 Re-scaling Velocity Sensor Input 9 - 8

C SERIAL COMMUNICATIONS 9 - 9

D AUXILIARY PRINTER 9 - 12

E GLOSSARY 9 - 13 Calibration Flow Chart 9 - 15

F TROUBLESHOOTING 9 - 17 OCM II Test Report

X FIGURES

Listing 10 - 1

91/02/14PL-269 ii

USERS GUIDE TO MANUAL

Although the OCM II may appear complex due to the diversity of applications it may be programmed for, it is infact quite simple in the confines of a particular application.

By adhering to the following suggestions, it will be found that the OCM II is quick and easy to calibrate.

STEP ONE Sections I through V should be read in order that the user may be familiarized with the OCM II.

STEP TWO

Refer to Table 3 listing the "P" parameters. Establish the values or codes to be entered for the parametersrequired. Write (pencil) these onto the calibration flow chart, or a photocopy, for each device you have and circlethe corresponding units or mode.

STEP THREE

Refer to Table 4 listing the "U" parameters. As there are many different types of flow applications, it will greatlysimplify matters for the user to select the one that fits his requirements and to disregard all others. Establish thevalues or codes to be entered for the parameters required. Write these onto the calibration flow chart andcircle the corresponding units or mode.

STEP FOUR

Now that all the data required to perform the calibration has been copied onto the calibration flow chart, followthe flow chart and enter your parameter values in order as prompted by the OCM II.

Should you require assistance in determining your application type, contact Milltronics or your distributor.

PL-269 iii

SECTION I

GENERAL INFORMATION

The Milltronics OCM II Open Channel Metering system is comprised of a NEMA 4 enclosed, microprocessorbased electronic package, ultrasonic transducer and solid state temperature sensor.

The OCM II system employs the principle of echo ranging to determine level. The OCM II transducer emits aprecisely defined burst of ultrasonic energy. The echo reflected from the liquid surface, delayed in time relativeto the distance travelled, is received by the transducer. This time interval, between transmitted pulse and receivedecho, is electronically processed into a digital indication of the target level or head.

The OCM II monitors the head of any liquid which flows with free surface in natural or fabricated open channels,as well as in partially or totally enclosed pipes.

Many open channels utilize specific weirs or flumes to restrict flow in a manner that permits the use of preciseflow calculation formulae. The OCM II was designed to permit the operator to enter information specific to theapplication into the battery protected memory via the front panel keypad.

The OCM II derives the flowrate from the head measurement which is totalized and stored in a data log to providea detailed flow analysis. In some cases the use of a velocity sensor to determine the flow velocity may be requiredto perform a flow calculation. The OCM II provides the excitation voltage required to operate such a device.

Special emphasis has been placed on providing the most accurate flow calculations possible. To that end, specificroutines have been written to comply with the British Standards Institute’s Specifications BS-3680. These routinescalculate correction factors that take into account second-order effects such as approach velocity and boundarylayer effects.

The OCM II Universal Flow Calculation features may be utilized where the flow is unrestricted or where the weiror flume used is not otherwise specifically listed in Table 4 of this instruction manual.

The LCD display, analog mA output, relay contact closure, and serial communication data link provided, may beprogrammed as desired, to provide local and/or remote access to a wide variety of detailed flow information.

PL-269 1 – 1

SECTION II

SPECIFICATIONS

Power - standard - 115/230 V ±10%, 25 VA, 50/60 Hz

- special - 100/200 V ±10%, 25 VA, 50/60 Hz

- optional - +24 V DC ± 10%, 25 VA

Fuse - 1/4 amp MDL Slo-Blo or equivalent

Range - 0.6 to 3.0 M (2 to 10 ft)

Transducer - model ST-25B or C, OCM grade

- CPVC body with polyurethane face

- 1" NPT mounting / conduit connection

- totally encapsulated

- carries CSA, FM and BASEEFA approvals for hazardous locations.

Operating - electronics - – 20 to 60 °C (– 5 to 140 °F)Temperature

- transducer - – 40 to 93 °C (– 40 to 200 °F)

- optional - 115 V AC, 125 VA thermostatically controlled heater available, where electronics operating temperature may fall below – 20 °C (– 5 °F)

Outputs: - transducer - 600 V peak to peak pulses of 0.5 msec. duration every 90 msec. drive

- anolog - 0-20 or 4-20mA DC isolated current output into 750 ohms maximum; proportional to: head, flow or velocity

- relay - one relay * form C (SPDT) contact rated 5 A @ 220 V AC, non-inductive to serve either alarm, totalizing or sampling functions

- optional Satellite Dual Alarm or Satellite Pump Module. Refer to instruction manual PL-232.

Resolution - 0.2 mm

92/07/07PL-269 2 – 1

* The relay is certified for use in equipment where the short circuit capacity capability of the circuits in which they are connected is limited by fuses having ratings not exceeding the rating of the relays.

Temperature - one temperature sensor inputCompensation

- error: - without temperature sensor: 0.17%/ °C- with temperature sensor: 0.09%

- optional Temperature Sensor

Data logs - 45 days flowrate and daily total flow

Display - two LCD displays for entry and read-out

Data Link - data logs may be retrieved or reset via RS232C compatible link at one of 4 baud rates: 9600, 2400, 1200 or 300.

- will output to a serial printer at regular intervals or on demand.

Temperature Sensor - model - TS-2 (optional)

- range - – 40 to 70 °C (– 40 to 158 °F)

- construction - PVC body- totally encapsulated

- resistance - 9.53 KΩ (nominal) at 20 °C (68 °F) ± 5 KΩ temperature variance

- separation - 183 m (600 ft) from OCM II under specified conditions. Refer to cabling

- approvals - CSA, FM and BASEEFA

- shipping weight - 0.5 Kg (1lb)

Cabling (optional) - transducer - RG-62U coax

- max. distance to OCM II: 183 M (600 ft)

- must be run in grounded metal conduit

- temp. sensor - Belden 8760, 1 pair shielded / twisted, 18ga

- max. distance to OCM II: 183 M (600 ft)

- can be run in same conduit with transducer cable

- data link - Belden 9553, 3 pair shielded/twisted, 18ga

- cable length: min. possible, max. 5 M (50 ft.)

PL-269 2 – 2

Battery - RAM back-up - 3 volt lithium, PC mount

- operating life: 1 year

- Duracell type DL-2025 Eveready, Sanyo or GE type CR-2025 Ray-O- Vac or Panasonic CR-2016.

Enclosure - Nema 4 thermoplastic with hinged clear polycarbonate door

Weight - transducer: - 0.9 Kg (2 lb)

- OCM II: - 6.8 Kg (15 lb)

- temp sensor: - 0.45 Kg (1 lb)

PL-269 2 – 3

SECTION III

INSTALLATION

OCM II

The OCM II should be mounted in a clean dry area; within the operating temperature range and non-corrosiveto, the electronics and the NEMA 4 polycarbonate enclosure. The enclosure door should be accessible to allowcalibrating and viewing. Refer to Figure 1 for outline and mounting details.

Do not mount the OCM II in direct sunlightwithout the use of a sun shield

BATTERY

After mounting the OCM II, open the cover and remove the front panel by loosening the captive thumb screws.

The unit is supplied with one battery package. Remove the battery from the package and insert it into either ofthe two battery sockets. The second battery socket is for installing a new battery before removing the old one,so as not to loose calibration and data logged into the memory.

Do not install the memory back-up battery until the OCM II is to be powered and put into use.

A battery installed in a non-powered unit will be drained in about one year. Remove the battery during extendedshut down.

TRANSDUCER

Transducer wiring must be done in conjunction with approved conduit, boxes and fittings and to procedures in accordance with all governing regulations.

All transducer wiring must be run in grounded metal conduit for optimum noise rejection. Ground shield only atOCM II and insulate shield at junctions to prevent inadvertent grounding.

Refer to Figures 3 & 8 in the back of this manual for wiring information and Figure 5 for general mounting practices.

1. Mount the transducer such that it is centered over the flow at a minimum height of 60 cm (2 ft) above thehighest liquid level with its radiating face aimed directly down. "U" parameter drawings depicting transducerlocation are for reference only. Refer to the manufacturer of the primary measuring device for the specifiedpoint of head measurement.

2. Position the transducer such that its sound path is perpendicular to the liquid surface. Noting that thetransducer beam angle is about 12° (6° off vertical or a rise:run of 10:1), care must be taken to position thetransducer such that the sound path to the liquid surface is unobstructed and does not intersect the walls ofthe flume or weir.

91/02/14PL-269 3 – 1

TEMPERATURE SENSOR

Refer to figures 4 & 8 for mounting and wiring.

VELOCITY SENSOR (optional/not by Milltronics)

Connect the velocity sensor output to terminals 16,17 & 18 of TB-1 on the OCM II motherboard.

For virtually any cross sectional channel shape, a velocity sensor can be used in combination with the level fromthe transducer to calculate the flowrate.

The OCM II is factory set to accept a standard 1 to 5 volt signal from the velocity sensor (for a 4-20 mA signal,a 250 ohm 1/4 W resistor must be installed across TB1-16,17). However, the output from a velocity sensor withina range of 0 to 10 volts and having a minimum span of 2.5 volts may be used.

Refer to Appendix B for instructions on re-scaling the input for velocity sensors.

INTERCONNECTION

All wiring must be performed in conjunction with approved conduit, boxes and fittings and to procedures in accordance with all governing regulations.

Ensure the 9.53 Kohm load resistor across TB1-13, 14 is removed prior to temperature sensor connection.

If the optional data transfer link to a computer is used, the baud rate of the OCM II and computer must be thesame. This also applies to the serial printer if it is used. Set switch SW1 as follows:

SW1 POSITION BAUD RATE(toggle down at)

1 - 96002 - 2400 3 - 12004 - 300

For Baud rates of 75, 150, 600 or 4800, set all SW1 toggles down at "open" and solder a jumper (J4, J5, J6 orJ7) onto the main board. Connect the communication cable to TB1-25 to 30.

Refer to figure 2 and Appendix C, Hardware Consideration.

Make sure that jumpers are properly set for standard 115 V AC or 230 V AC or special 100 V AC or 200 V ACoperation. Refer to figure 2 or see diagram on motherboard.

The main fuse must be installed. When making the power connection ensure that wires are securely fastened tothe proper terminals.

Do not operate with ground (earthing) wire disconnected.

Flip the power switch located at the lower edge of the motherboard "ON" and re-install the front panel. The unitis now ready for start up.

91/02/14PL-269 3 – 2

SECTION IV

START UP

GENERAL

Calibration of the OCM II is done via the front panel keypad. To provide clarity, all keypad entries are enclosedwithin square brackets [ ] to distinguish them from other text.

The OCM II is designed to automatically prompt the user for each parameter in a particular sequence so thatnone will be missed. Each parameter that is entered is then incremented to the next step required for theselected primary element.

In order to prevent unauthorized or accidental alteration of data, all entries must be made through the access / program mode F0, accessible via the following security code:

2.71828

PL-269 4 – 1

KEYPAD

"A" Auxiliary Functions

Used to select auxiliary parameters for Universal Head vs Flow Calculation applications and perform printer functions.

"C" Clear

Used to clear reading display

"D" Display quantities

Enter [D#] [E]

Used to select any one of the ‘D’ displays

These are specific results of normal operation which the user may wish to view. The display mode iscontinuously updated even while viewing in the "F" program mode.

e.g. D2 - Accumulated flow

D5 - Target range (Important aid in trouble shooting)

Refer to Table 1 for listing.

"E" Enter

Used to enter keypad selection as displayed and/or to scroll forward through displays or parameters.

"F" Function Mode

Enter: [F#] [E]

Used to select any one of the ‘F’ functions for performing special tasks.

e.g. F0 - Access/Programming

F7 - Setting the date


"P" Parameters

Enter: [P#] [E]

Used to select anyone of the ‘P’ parameters.

These are code numbers or values entered to tailor the OCM II operating system to the users requirements.

e.g. P2 - Primary element being monitored

P9 - Relay setpoint


91/02/14PL-269 4 – 2

"R" Recall

Used to scroll backward through displays or parameters.

"U" Unit Parameters

Enter: [U#] [E]

Used to select any one of the ‘U’ unit parameters. These parameters set the physical characteristics uniqueto the primary element being monitored. They have been separated from the other parameters in orderthat the OCM II may prompt the user for each entry during calibration.

e.g. U0 - Expected flow at the calibration head

U3 - Exponent specific to the primary element


"0-9" Numeric Entries

" . " Decimal Point

" - " Negative Sign

KEYPAD ENTRY

Press desired keypad switches.

e.g. [P] [2]

Selection will be displayed in the "Reading" window.

Press [E] to enter selection.

Access parameters (U & P) or display and function code entries (D & F) are automatically shifted into the"Mode" window after entry. However, code selections and values remain displayed in the "Reading" window. After entry is made, mode is incremented to the next calibration step. If reading displays error, refer to Appendix A for error codes.

DISPLAY

P4 17.8 MODE READING

Display Description

F2 - H H indicates display of HEADF indicates display of FLOWA indicates display of TOTAL FLOW

ERR 6 ERROR MESSAGE NO. 6

LOE LOSS OF ECHO

- - - - NUMERIC OVERFLOW

PASS DIAGNOSTIC ROUTINE, F13

ACCESSRELAY

PL-269 4 – 3

INITIAL START UP

The memory back-up battery must be installed before turning the power switch on.

(refer to INSTALLATION section)

Flip SW-2 power switch ON. The OCM will display "F0" in the mode window and the transducer will begin firing.

The unit is now ready to be calibrated. Refer to the calibration chart, noting that:

After the access code is entered, the access light will illuminate confirming that the OCM II is accessible for programming.

After an entry is made, the reading window will display the factory setting.

EXAMPLE:

Enter: [F0] [E]

Enter: [2.71828] [E]

The prompt in the left window will change to P0 and programming may proceed.

P0 = 0 Centimeters

P0 = 1 Inches

If centimeters is chosen:

Enter: [0] [E] or simply [E] as the present value is 0.

The next parameter, P1, is now displayed:

P1 = 0 Temperature in degrees Celsius

P1 = 1 Temperature in degrees Fahrenheit

If temperature in Fahrenheit is chosen;

Enter: [1] [E]

The next parameter on display is P2, primary element. As listed in Table 3, P2 may be set to any one value from0 to 15, or 30 depending on the type of primary measuring device. The two following examples will illustrate theuse of this parameter.

PL-269 4 – 4

Example 1

BS-3680 triangular weir, when P2=6 is entered, the OCM II will switch to the list of unit parameters required forthat type of flow calculation. If the prompting sequence is followed, none of the unit parameters will beinadvertently omitted. The OCM II will switch back to "P" parameters once all necessary "U" parameters havebeen entered.

a) U0 = Qcal

This is the calibration flow, i.e. the flow that is expected to occur when the liquid level is at hcal, the calibrationhead. It may be entered in any engineering units and may be in units per second, units per minute, units perhour or units per day. In this case, hcal = 38 cm so that Qcal = 0.031273 m3 / s.

b) U1-time units of Qcal

We have chosen to have our calibration in flow units per second so we must enter U1 = 0.

c) U2 = hcal

This is the head at which the calibration flowrate defined by U1 and U2 will occur. In our case it is 38 cm.

d) U3 = The angle of the weir

We will also need to enter the angle of the weir’s V-notch which is 28 degrees 4 minutes or 28.06666 degrees.We shall use U3 = 28.07.

We shall now enter these values beginning with U0, which at this point is displayed in the prompt window.

U0 = 0.03127 Enter [0.03127] [E]

U1 = 0 Enter [0] [E]

U2 = 38 Enter [38] [E]

U3 = 28.07 Enter [28.07] [E]

Now the display in the prompt window switches to P3 so that the next "P" parameters can be entered.

PL-269 4 – 5

Example 2

Parshall Flume

Max. flow = 936 X 103 litres per day Max. head = 40 centimeters

Flowrate = K (Head)1.55 where K is a constant

1 Count = 1000 litres

Referring to Table 4 for "U" parameters, enter

P2 [0] [E] or simply [E] Primary element

U0 [936] [E] Max. flow

U1 [3] [E] Flow unit per day

U2 [40] [E] Max. head

U3 [1.55] [E] Exponential term

P3 refer to parameter listing Table 3.

P4 AND F12 AUTO ZERO ROUTINE

P4 is the distance measured from the face of the transducer to the level at which liquid flow will cease.

As the OCM II routinely measures the distance between the transducer and the liquid surface, it requires onlythe distance that the liquid surface is above the zero level to be given to calculate P4.

Alternately, the Auto Zero Routine F12, will make the required calculation and enter the appropriate value for P4automatically.

Enter: [F12] [E]

Enter: [current head]

"F12" & "calculation" will appear in the displays.

The current head is measured above the level at which flow would cease and must be in the units of measure selected by P0.

When all the P and U parameters have been entered, the unit may be placed in operation unless data loggingfunctions are required. In such a case it is necessary to set the internal clock and calendar. As the data loggingfunction may be used for trouble shooting it may be desirable to set the time and date regardless.

For parameters P5, P6, P7, P11, P12, P13, P14, P15, P16, P17, and P18. Refer to Table 3. These parametersare simple and self-explanatory from the list.

PL-269 4 – 6

SETTING THE CLOCK

To set the clock:

Enter: [F0] [E] (if not yet in access mode)

[2.71828] (access code) [E]

Enter: [F5] [E]

Enter: [hhmmss] [E] The current time in 24 hour format where h = hoursm = minutess = zero seconds

e.g. 2:07:15 P.M. = 14:07:15 = 140700

The clock always sets seconds to zero. If the precise setting is required, set the clock to the next minute and press the "enter" key at the appropriate moment.

SETTING THE CALENDAR

To set the calendar


[2.71828] (access code) [E]

Enter: [F7] [E]Enter: [ddmmyy] [E] The current date where d = day

m = monthy = year

e.g. July 11th, 1981 = 110781

The clock continues to keep time during a power failure. This insures that data entered upon power resumption is correctly referenced.

When the calibration phase has been completed the OCM II may be placed in normal running mode by:

Entering: [F2] [E] The access light will extinguish.

PL-269 4 – 7

SECTION V

DAILY OPERATION

When the OCM II system has been placed in normal running operation, F2, all of its operating parameters arepreserved in the battery protected memory. In the event of a power failure the system will be brought back up innormal F2 mode of operation with logs and totalizers saved with the data prior to this power failure. The clockkeeps the correct time.

The transducer is fired every 90 mSec and the echo processed to determine the head (D0). Flowrate (D1) iscalculated by the OCM II as a mathematical function of head or a function of head and velocity. The flowrate isthen integrated to yield the totalized flow (D2). The "Reading" display is continuously updated and can be set(P3) to display head, flowrate or total flow when in the F2 mode.

At any time during normal operation, display quantities such as: head, flow, temperature or % of total flow canbe viewed by entering [D#] [E]. Entering [F2] [E] will return system to normal operation. Refer to Table 1 for thecomplete list of display quantities.

The current time or date can be verified by entering F4 or F6 respectively.

An alarm relay is provided and may be assigned to monitor high or low head or flow, or to serve as a contactactuated by either time or total flow (P8). When the relay is designated as an alarm, it is energized during normaloperation. Under alarm conditions, the relay is de-energized and the front panel "Relay" light is illuminated.

The relay set point level is programmable (P9) in units corresponding to its assignment with a deadband set byP10. When the relay is designated as a totalizer or sampler contact, it is normally de-energized. As a totalizercontact, the relay is energized each time the displayed total increases by the amount entered into P9. As a samplercontact, the relay is energized at the rate of the time period entered into P9 in units of minutes. Duration of contactclosure is 400 mSec, suitable for driving a mechanical totalizer or sampler.

In the event that there is a loss of echo and the loss of echo time-out (P7) expires, one of three possible actions(P6) can be taken.

1. Hold: 4 - 20 mA current output and alarm relay hold their previous status. Totalizer continues to totalize at previous rate.

2. Fail-safe low:

4 - 20 mA current output drops to minimum value as set by P13 and alarm relay de-energizesif programmed (P8) for low head or flow. Totalizer totalizes at minimum rate.

3. Fail-safe high:

4 - 20 current output rises to 20 mA and alarm relay de- energizes trips if programmed (P8) for high head or flow. Totalizer totalizes at maximum rate.

If the clock and calendar have been set, flowrates are logged at 15 minute intervals (F9) and flows are totalizedto yield a log of daily flow totals (F10) for a period of 45 days. Flow is also totalized with respect to its percentageof the calibrated maximum flowrate (Qcal) in increments of 10% (D10 to D21). For example, if the current flow is65% of Qcal, then the flow will be totalized in the 60 -70% (D6) totalizer. These totalizers establish a flowrateprofile showing how much flow has occurred in any 10% segment of the calibrated flow.

PL-269 5 – 1

In addition to the aforementioned totalizers, a serial port totalizer (D22) is provided. It is incremented at the samerate as D2, but may be viewed or reset by serial communication (refer to Appendix C).

The data logging buffers are configured as ring buffers, capable of storing 45 days of flow information. Following45 days, further data logs will be stored commencing from the day 1 location again. The OCM II always clearsthe next days buffer one day in advance. Therefore a power disruption of less than one day will not leavepreviously stored information in that day’s data log location.

TO VIEW THE FLOWRATE LOG:

Enter: [F9] [E]

The OCM II will display a random record which is to be ignored.

Enter: [ddmmyy] [E]

The OCM II will respond with the time 00:00 in the mode window and the corresponding average flowrate of theprevious 15 minute interval will appear in the reading window. Pressing [E] once will step to the next 15 minuteinterval or [R] to step backwards. If either [E] or [R] is held, the display will scroll rapidly through the logged data.

If there is no data recorded in the log for the requested date, the reading will indicate error code E9.

TO VIEW A DAILY FLOW TOTAL:

Enter: [F10] [E]

The OCM II will display a random message which is to be ignored.

Enter: [ddmmyy] [E]

The OCM II will respond by showing the date in the mode window and the corresponding day total in the readingwindow. Pressing [E] once will step to the next day interval or [R] to step backwards. If either [E] or [R] is held,the display will scroll rapidly through the logged data.

If there is no data recorded in the log for the requested date, the reading will indicate error code E9.

PL-269 5 – 2

SECTION VI

AUXILIARY OPERATIONS

F1 EMULATION MODE

The flow calculation parameters can be checked for accuracy by using the emulation function, F1. A liquid head is entered via the keypad and the OCM II will respond by displaying the flow associated with that head. During emulation mode, all totalizing stops. This feature may be used to find a head that is equal to a flowrate that will suit the chart recorder better.

e.g. If the maximum flowrate of a system is 721.6 litres / second, however the desired maximum flowrate is 700 litres / second the operator may key in head values to find the head value required to produce the desired flowrate.

Enter: [F0] [E] (if not yet in the access mode)

[2.71828] [E]

"P0" will appear

Enter: [F1] [E]

[HEAD1] [E]

"FLOW" corresponding to HEAD1 will be displayed.

Enter: [HEAD2] [E]

"FLOW" corresponding to HEAD2 will be displayed, etc...

F3 CLEARING TOTALIZERS

Used to clear all totalizers. This will zero displays: D2, accumulated flow; D10-D21, % of accumulated flow and D22, serial port totalizer


[2.71828] [E]

"P0" will appear

Enter: [F3] [E]

[2.71828] [E]

"clr" will appear, indicating that the totalizers have been cleared.

PL-269 6 – 1

F11 CLEARING THE LOG BUFFERS

Used to clear the log buffers. This will zero displays: F9, flowrate log and F10, daily flow totals log.


[2.71828] [E]

"P0" will appear

Enter: [F11] [E]

[2.71828] [E]

"clr" will appear, indicating that buffers have been cleared.

F13 DIAGNOSTIC ROUTINE

The OCM II has a built in diagnostic routine which performs operational checks on the system and tests both RAM and ROM memory.

The routine will indicate "PASS" in the reading window to indicate that the system is functional. Should it fail, "FAIL" will appear with the address being written into D23 (ROM) or D24 (RAM) to record failure location.

Enter: [F13] [E]

F14 FORCED COLD START

To force a cold start in order to completely reprogram the system.

NOTE: This will erase all previous programming and data logs. In the event of a surge in power supplied to the OCM II, perhaps as the result of a nearby lightning strike, it may be necessary to force a cold start. This condition may be diagnosed by: Display filled with 8’s, keypad accessloss, erratic display, or incorrect level measurement.


[2.71828] [E]

"P0" will appear

Enter: [F14] [E]

[2.71828] [E]

"F0" will appear

Enter: [2.71828] [E]

"P0" will appear. Refer to calibration flow chart and procedures for initial start-up.

PL-269 6 – 2

RECALIBRATION

To revise a few parameters so that no others are altered or no data logging is lost:

Enter: [F0] [E]

[2.71828] [E]

"P0" will appear

Enter desired [P#] or [U#] and [E]

Revise parameter contents

To reset or preset a display totalizer

Enter: [F0] [E]

[2.71828] [E]

"P0" will appear

Enter desired [D#]

Reset display by entering clear [0] [E]

Preset display by entering amount [####] [E]

PL-269 6 – 3

TABLE 4

UNIT PARAMETERS FOR THE PRIMARY ELEMENT PARAMETER P2

The number of unit parameters required varies according to the primary element chosen. The OCM IIsoftware will prompt the user by displaying the next parameter, thereby insuring that all the requiredparameters are entered.

In the case of BS-3680 devices, certain values are calculated and stored with the entered values where theymay be viewed by the user.

The following is a list of the types of primary elements for which the OCM II has been programmed.

Refer to the page covering your particular application; the rest may be disregarded.

For applications other than those listed, please contact Milltronics or your distributor.

P2 DESCRIPTION PAGE

0 Simple exponential device 7 – 13 1 Rectangular throated flume 7 – 15 1 Round-nose horizontal crest weir 7 – 17 2 Trapezoidal throated flume 7 – 19 3 U-throated flume 7 – 21 4 Rectangular-profile weir 7 – 23 5 Rectangular-notch weir 7 – 25 6 Triangular-notch weir 7 – 27 7 Compound exponential devices 7 – 29 8 Velocity-area product 7 – 31 9 Round pipe 7 – 3310 Palmer-Bowlus (Plasti-Fab or Warminster) 7 – 3511 H-flume 7 – 3712 U Channel, Velocity-Area Product 7 – 3913 Trapezoidal Bottom Channel, Velocity-Area 7 – 4114 Unlisted Channel, Velocity-Area Relationship 7 – 4315 Unlisted Head-Flowrate Relationship 7 – 4530 Round Pipe, Velocity-Area product 7 – 47

The above devices must be installed in accordance with the manufacturers recommendations and/or guidelines published by applicable

standards organizations or governing agencies.

PL-269 7 – 9

TYPICAL SHARP-CRESTED WEIRS

Rectanglar - suppressedU3 = 1.5

Trapezoidal (Cipolletti)U3 = 1.5

Sutro (Proportional)U3 = 1

(symmetrical or asymmetrical)

Q

minimum 3 h max

h

transducer location

Typical Weir Installation

V - notch or TriangularU3 = 2.5

For rated flows under free flow conditions, the head is measured upstream of the weir plate at a minimumdistance of 3 times the maximum head (i.e. where the liquid surface is not effected by drawdown). Theminimum allowable distance from transducer to maximum liquid level is 60 cm (2 ft.)

PL-269 7 – 10

KHAFAGI VENTURI

TYPICAL PARSHALL FLUME

throatdiverging

15 cm (6")

transducer *

converging

0headside front

plan

For rated flows under free flow conditions, the head is measured 15 cm (6") upstream from the beginning of the converging section.

0 head

2/3 C

C

transducer *

plan

side

Q

For rated flows under free flow conditions, the head is measured at 2/3 the length of the converging section upstream of the beginning of the throat section.

* Position the transducer such that it is centered over the flow at a minimum height of 60 cm (2ft) above the maximum head.

PL-269 7 – 11

TYPICAL LEOPOLD LAGCO

divergingconverging

Q

0 head

point of measurement

side front

transducer

transducer plan

throat

For rated flows under free flow conditions, the head is measured at a point upstream referenced to thebeginning of the converging section. Refer to the following table.

Position the transducer such that it is centered over the flow at a minimum height of 60 cm ( 2ft ) above themaximum head.

Flume Size Point of Measurement(pipe dia. in inches) mm inches

4 - 12 25 1.015 32 1.318 38 1.521 44 1.824 51 2.130 64 2.536 76 3.042 89 3.548 102 4.054 114 4.560 127 5.066 140 5.572 152 6.0

PL-269 7 – 12

P2=0 SIMPLE EXPONENTIAL DEVICES

U0 = Qcal The flowrate at full head

enter: [value from specs.]

U1 = tcal The time units of Qcal

enter: [0] per second[1] per minute[2] per hour[3] per day

U2 = hcal The head at which Qcal occurs


U3 = exponent

enter: [1] Sutro (proportional) weir[1] Head measurement only[1.5] Rectangular (suppressed) or Trapezoidal (Cipolletti) weir[1.5] Kahfagi venturi[1.55] Parshall flume[1.55] Leopold Lagco[2.5] Triangular (V-notch) weir[x] or any exponent required

Refer to manufacturers specifications for the exact exponent. The exponents listed above are shown for reference only.

Free flowrate is given by: Q = Qcal x (h/hcal)exponent

PL-269 7 – 13

RECTANGULAR THROATED FLUME

L

B

3 h to 4 h

b

h

plan view

elevation

p

flow

transducer location[min.distance from transducer to max. liquid level is 60 cm (2ft)]

PL-269 7 – 14

P2=1 BS-3680 RECTANGULAR THROATED FLUME







U3 = b Width of throat


U4 = B Width of approach channel


U5 = p Height of hump


U6 = L Length of throat


VALUES CALCULATED BY OCM II

U7 = m Side slope (0 for rectangular flume)U8 = Cv Velocity coefficient at current headU9 = Cs Shape coefficient (1 for rectangular flume)U10= Cd Discharge coefficient at current headU11= A Area of cross section of flow in approach channelU12= Cvcal Velocity coefficient at hcalU13= Cdcal Discharge coefficient at hcalU14= Cscal Shape coefficient (1 for rectangular flume)U15= h The liquid head

The flowrate is given by: Q = Qcal x Cv/Cvcal x Cd/Cdcal x Cs/Cscal x (h/hcal)1.5

PL-269 7 – 15

ROUND NOSE HORIZONTAL CREST WEIR


L

p

hb

B

3 h to 4 h

PL-269 7 – 16

P2=1 BS-3680 ROUND-NOSE HORIZONTAL CREST WEIR







U3 = b Width of weir crest


U4 = B Width of approach channel (usually equal to U3)


U5 = p Height of weir crest above bed level


U6 = L Length of crest in direction of flow



U7 = m Side slope (0 for RNHC weir)U8 = Cv Velocity coefficient at current headU9 = Cs Shape coefficient (1 for RNHC weir)U10= Cd Discharge coefficient at current headU11= A Area of approach channelU12= Cvcal Velocity coefficient at hcalU13= Cdcal Discharge coefficient at hcalU14= Cscal Shape coefficient (1 for RNHC weir) U15= h The liquid head above weir crest

Flowrate is given by: Q = Qcal x Cv/Cvcal x Cd/Cdcal x Cs/Cscal x (h/hcal)1.5

PL-269 7 – 17

TRAPEZOIDAL THROATED FLUME


b

1

m

B

bB

3 h to 4 h

L

p

transducer

side slope

plan view

elevation

p

flow

h

PL-269 7 – 18

P2=2 BS-3680 TRAPEZOIDAL THROATED FLUME







U3 = b Width of flume throat






U6 = L Length of prismatic section of the contraction


U7 = m Side slope (m horizontal : 1 vertical)



U8 = Cv Velocity coefficient at current headU9 = Cd Discharge coefficient at current headU10= Cs Shape of coefficient at current headU11= A Area of cross section of flow in approach channelU12= Cvcal Velocity coefficient at hcalU13= Cdcal Discharge coefficient at hcalU14= Cscal Shape coefficient at hcalU15= h The liquid headU16= eta A numerical coefficient which varies with m

Flowrate is given by: Q = Qcal x Cv/Cvcal x Cd/Cdcal x Cs/Cscal x (h/hcal)1.5

PL-269 7 – 19

U-THROATED FLUME


plan view

L

Da

3 h to 4 h

h

p

elevation

D

PL-269 7 – 20

P2=3 BS-3680 U-THROATED FLUME







U3 = D The diameter of flume throat


U4 = Da Diameter of approach channel




U6 = L Length of prismatic section of the contraction



U7 = m Side slope (0 for U-throated flume)U8 = Cv Velocity coefficient at current headU9 = Cd Discharge coefficient at current headU10= Cu Shape coefficient at current headU11= A Area of cross section of flow in approach channelU12= Cvcal Velocity coefficient at hcalU13= Cdcal Discharge coefficient at hcalU14= Cucal Shape coefficient at hcalU15= h The liquid head

Flowrate is given by: Q = Qcal x Cv/Cvcal x Cd/Cdcal x Cu/Cucal x (h/hcal)1.5

PL-269 7 – 21

RECTANGULAR PROFILE WEIR


3 h to 4 h

L

p

h

PL-269 7 – 22

P2= 4 BS-3680 RECTANGULAR-PROFILE WEIR







U3 = p Height of weir above bottom of approach channel


U4 = L Width of the weir in the direction of flow



U5 = C Coefficient of discharge at current headU6 = Cp Correction factor for C (varies with h/p)U7 = Ccal Coefficient of discharge at hcalU8 = Cpcal Correction factor for C at hcal

Flowrate is given by: Q = Qcal x C/Ccal x Cp/Cpcal x (h/hcal)1.5

PL-269 7 – 23

RECTANGULAR NOTCH WEIR


h

p

B

b

4 h to 5 h

PL-269 7 – 24

P2=5 BS-3680 RECTANGULAR-NOTCH WEIR







U3 = b Width of the notch




U5 = p Height of the crest above the bottom of the approach channel



U6 = m Side slope (0 for rectangular weir)U7 = Ce Coefficient of discharge at current headU8 = Cecal Coefficient of discharge at hcal

Flowrate is given by: Q = Qcal x Ce/Cecal x (h+kh/hcal+kh)1.5 ; kh = 0.1 cm

PL-269 7 – 25

TRIANGULAR-NOTCH WEIR

h

p

B

b

transducer location [min. distance from transducer to max. liquid level is 60 cm (2ft)]

a°

4 h to 5 h

PL-269 7 – 26

P2=6 BS-3680 TRIANGULAR-NOTCH WEIR




enter: [0] per second[1] per minute[2] per hour

[3] per day



U3 = alpha (a) Angle of V in degrees



U4 = Ce Coefficient of discharge at current headU5 = Cecal Coefficient of discharge at hcal

Flowrate is given by: Q = Qcal x Ce/Cecal x (h/hcal) 2.5

PL-269 7 – 27

SHARP CRESTED RECTANGULAR CONTRACTED WEIR

minimum 3 Hmax H

Q

transducer location [min. allowable distance from transducer to maximum liquid level is60 cm (2ft) ]

Q = 3.33(L-0.2H) H1.5

= 3.33LH1.5 - 0.666H2.5

where: Q = flow in cubic ft per second H = head in ft L = crest length in ft

thus: A = 3.33L B = -0.666

For rated flows under free flow conditions, the head is measured upstream of the weir plate at a minimumdistance of 3 times the maximum head (i.e. where the liquid surface is not effected by drawdown).

L

PL-269 7 – 28

P2=7 COMPOUND EXPONENTIAL DEVICES


enter: [values from specs.]





U3 = A Coefficient of the 1st exponential term


U4 = B Coefficient of the 2nd exponential term


Flowrate is given by: Q = Qcal x (A x h1.5 + B x h2.5) (A x hcal1.5 + B x hcal2.5)

Example for the thin plate rectangular notch weir where

Q = 3.33 (L-0.2h)h1.5 A = L (same units as in P0)B = -0.2

PL-269 7 – 29

FLOW BY VELOCITY - AREA PRODUCT

1transducer location [min. distance from transducer to max. liquid levelis 60 cm (2ft) ]

h

Q

area = h(b+mh)

side slope

b

m

PL-269 7 – 30

P2=8 VELOCITY-AREA PRODUCT

U0 = Qcal The flowrate at full head and max. liquid velocity






U3 = vsensor Full scale reading of velocity sensor in (the chosen) linear units per second


U4 = vcal The maximum liquid velocity in the same units


U5 = b Width of the channel at its base


U6 = m Side slope (m horizontal : 1 vertical)


Flowrate is given by: Q = Qcal (h(b+mh)v / (hcal(b+mhcal)vcal) )

PL-269 7 – 31

ROUND PIPE

min.60 cm(2 ft)

h max

transducer location (refer to figure 7)

r

45.7 cm (18 ") maximumstandpipe length

PL-269 7 – 32

P2=9 ROUND PIPE







U3 = r Pipe inside radius

enter: [value from specs.] (min. 6 inches)


U4 = h Current headU5 = f(h) A function of the current headU6 = f(hcal) A function of hcalU6 = f(hcal) A function of hcalU7 = Q The current rate of flow

Flowrate is given by:

Q = Qcal f(h)f(hcal)

pi h-r((h-r)(r2-(h-r)2).5 + r2 (2 + arcsin( r )))

1.67

f(h) = (r (pi + 2arcsin(h-r)))0.67

r

PL-269 7 – 33

TYPICAL PALMER-BOWLUS FLUME(as manufactured by Plasti-Fab or Warminster Fiberglass)

Dtransducer

D = pipe or sewer diameter

D/2 point of measurement

0head

Q

For rated flows under free flow conditions, the head is measured at a distance of D/2 upstream from thebeginning of the converging section.

Position the transducer such that it is centered over the flow at a minimum height of 60 cm (2ft) above themaximum head.

PL-269 7 – 34

P2=10 PALMER BOWLUS FLUME







U3 = Qmax The max. flow capability of the flume


U4 = hmax The head at which Qmax occurs


PL-269 7 – 35

TYPICAL H-FLUME

point of measurement

transducer

D

plan

front side

Q

For rated flows under free flow conditions, the head is measured at a point downstream from the flumeentrance. Refer to the following table.

Flume Size Point of MeasurementD (feet) cm inches

0.5 4.7 1.880.75 6.7 2.691.0 9.1 3.631.5 13.5 5.382.0 17.9 7.192.5 22.5 9.003.0 27.2 10.884.5 40.5 16.19

Position the transducer such that it is centered over the flow at a minimum height of 60 cm (2ft) above themaximum head.

PL-269 7 – 36

P2=11 H-FLUME







U3 = Qmax The max. flow capability of the H-flume


U4 = hmax The head at which Qmax occurs


PL-269 7 – 37

U-CHANNEL VELOCITY AREA PRODUCT

V

r

h

Center transducer over channel.Minimum distance from transducer face tomaximum head is 60 cm (2ft)

PL-269 7 – 38

P2 = 12 U CHANNEL, VELOCITY-AREA PRODUCT



U1 = tcal the time units of Qcal




U3 = vsensor Full scale reading of velocity sensor in (the chosen) linear units per second at 5 volt input.




U5 = r radius of channel bottom

Flowrate is given by: Q = Qcal x area(h)/area(hcal) x v/vcal

PL-269 7 – 39

TRAPEZOIDAL BOTTOM VELOCITY AREA


bV

BV - Channel h ≤ ht, b=0

Trapezoidal Channel h ≤ ht, b ≠ 0

Modified - Trap h > ht, b ≠ 0

Rectangular Channel B = 0

h

ht

PL-269 7 – 40

P2 = 13 TRAPEZOIDAL BOTTOM CHANNEL, VELOCITY-AREA PRODUCT

U0 = Qcal The flowrate at full head at velocity vcal










U5 = b width of the bottom of the channel

U6 = B width of the top of the channel

U7 = ht height of transition to vertical section of the channel


NOTE: This formula will work with a V bottom (b=0) or Rectangular channels (b=B).

PL-269 7 – 41

UNIVERSAL VELOCITY - AREA FLOW CALCULATION


V

Cross Sectional Area

Head

A1AN

h

A2

H1

A0 A5A3 A4

H3

H4

H5

Hn

H2

H0

( E

qual

Incr

emen

ts )

PL-269 7 – 42

P2 = 14 UNIVERSAL VELOCITY-AREA FLOW CALCULATION

From the Head vs Cross Sectional Area graph for the primary element, divide the head axis of the graph into equal increments.

Sequentially assign each increment an "A" parameter number starting from "A0" at 0 head to a maximum of "A31". Flow accuracy improves with the number of "A" parameters used.

From the graph determine the channel cross sectional area associated with each head increment and enter this as the value of the assigned "A" parameter.

U0 = Qcal the flowrate at full head at velocity vcal










U5 = N the last "A" parameter number assigned. (AN)

enter: [N]

U6 = hmax the highest head to be entered, associated with parameter AN

enter: [value from graph]

A0 = area at 0 head

enter: [0] as head is equal to 0

A1 = area 1 the channel cross sectional area at head increment 1


AX = area X the channel cross sectional area at head increment X. Continue to enter points from graph until AN.enter: [value from graph]

Note: "A" parameters need to be accessed and exited by [A0] [E] or [P3] [E]. "A" parameter values may be entered as a percentage if desired.

%AX value = AX value x 100 AN value

PL-269 7 – 43

UNIVERSAL HEAD vs. FLOW CALCULATION

FlowrateA1

ANA2 A4A0


Vh

A5A3

HN

H5

H4

H3

H2

H1

H0

head

( E

qual

Incr

emen

ts )

PL-269 7 – 44

P2 = 15 UNIVERSAL HEAD vs. FLOW CALCULATION

From the Head vs Flowrate graph for the primary element, divide the head axis of the graph into equal increments.

Sequentially assign each increment an "A" parameter number starting from "A0" at 0 headto a maximum of "A31". Flow accuracy improves with the number of "A" parameters used.

From the graph determine the flowrate associated with each head increment and enter this as the value of the assigned "A" parameter.

U0 = Qcal the flowrate at full head




U2 = hcal the head at which Qcal occurs


U3 = N the last "A" parameter number assigned (AN).

enter: [N]

U4 = hmax the highest head to be entered, associated with parameter AN


A0 = flow at 0 head

enter: [0] as head is equal to 0

A1 = flow 1 the flow at head increment 1.


AX = flow x the flow at head increment X, continue to enter points from graph until AN.


Note: "A" parameters need to be accessed and exited by [A0] [E] or [P3] [E]. "A" parameter values may be entered as a percentage if desired.

% AX value = AX value x 100 AN value

PL-269 7 – 45

ROUND PIPE, VELOCITY - AREA PRODUCT

min.60 cm(2 ft)

h max

transducer location (refer to figure 7)

45.7 cm (18 ") maximumstandpipe length

PL-269 7 – 46

P2 = 30 ROUND PIPE, VELOCITY-AREA PRODUCT











U5 = r radius of pipe


PL-269 7 – 47

SECTION VIII

MAINTENANCE

The OCM II requires very little maintenance due to its solid-state circuitry. However, a program of periodicpreventative maintenance should be initiated. This should include regular inspection, general cleaning,transducer face inspection, overall system performance checks and standard good housekeeping practices.

A periodic inspection of the transducer is recommended, at which time any build-up of material on the transducershould be removed.

The enclosure and circuit board should be cleaned only when the power is disconnected at the main breaker andusing a vacuum cleaner and a clean, dry paint brush. Check all electrical contacts for signs of corrosion or arcing.

The memory back-up battery must be replaced every year to prevent memory loss in the event of a power interruption.

- remove the front cover

- flip the power switch to ‘OFF’

- insert the new battery into the spare socket

- remove the old battery from the other socket

PL-269 8 – 1

APPENDIX A

ERROR CODES

1. Numeric underflow: probably a bad U parameter or incorrect flow program P2.

2. Numeric overflow: probably a bad U parameter or incorrect flow program P2. P9 to small, relay ispulsing once every 2 seconds until the totalizer is overflowed at high flowrates.

3. Attempt to divide by zero: check parameter entries.

4. Bad argument (e.g. attempted square root of a negative number): check parameter entries.

5. Attempt to access non-existent parameter.

6. Access to parameters denied: security code has not been entered.

7. Primary element exceeds BS-3680 dimensions or head exceeds the max. range of BS-3680 specifications; bad U parameter.

8. Conversion overflow (long floating point to short floating point):

Inappropriate choice of flow or time units, (U0 or U1) causing logging total overflow.

Bad U parameter causing excessive flowrate to be calculated.

9. Requested date is not in data log:

date has not been entered in correct format.

calendar was not set correctly on start up.

10. Attempt to select non-existent primary element of P2

PL-269 9 – 1

APPENDIX B

EXAMPLE 1: PARSHALL FLUME

This example considers a 6 inch Parshall flume which has a maximum flowrate of 1.87 MGPD at 1.24 feet of head.

The transducer has been mounted 30 inches above the maximum operating head (at least 24 inches required).

The maximum liquid head is 1.24 feet = 14.88 inches.

The manufacturer‘s flow table shows flow as MGPD = 1.33 h1.58 . Thus the flume is characterized by an exponentof 1.58.

The distance from the transducer face to the zero-flow liquid level is 30 inches plus 14.88 inches = 44.88 inches.

An alarm is required for liquid levels in excess of 13.6 inches.

P0 = 1 Dimensions are in inches P1 = 1 Temperature is FahrenheitP2 = 0 Exponential flow calculationU0 = 1.87 MGPD (million gallons per day) at full head for 20mA output [or 1870 to have units

of 1000 gallons]U1 = 3 Flowrate time units (per day)U2 = 14.88 Full scale head in inches at 1.87 MGPDU3 = 1.58 ExponentP3 = 1 Display flowrate in run mode (F2)P4 = 44.88 *Distance from transducer to 0 flowrate head in inchesP5 = 0 Calculate flow for all heads (no low head cut off)P6 = 1 Fail safe highP7 = 60 Fail safe after 60 seconds without an echoP8 = 1 High alarm for high liquid headP9 = 13.6 Head at which alarm is to occurP10 = 3 Head must fall by 3 inches to cancel alarmP11 = 0 Analog output is to represent flowrateP12 = 20 Damping rate is 20 seconds for 100% changeP13 = 0 Analog output is 4-20 mAP14 = 192 Optional logging file site identification numberP15 = 1 Totalizer multiplier [the floating point totalizer will move the decimal point to the right

until only whole units are displayed. Therefore it is advisable to use units of one thousands rather than millions. [Conversely the units can be left at millions and the multiplier set at .001]. Totalizer overflows every 534 days at full-scale flowrate of 1870 thousand gallons per day.

P16 to P18 not used in this example

* If AUTO ZERO calibration routine (F12) is used, entry of the current liquid head will cause P4 = 44.88to be deduced and entered automatically.

N.B. Data Logging occurs automatically and requires no specific set-up. However, the data logs will bemeaningless if the CLOCK and CALENDAR are not set to the present time and date. If data logs will never be used the clock and calendar need not be set. However for trouble shooting it may be useful by noting when an abnormally high or low reading is occurring.

PL-269 9 – 2

EXAMPLE 2: RECTANGULAR FLUME (BS-3680)

This example considers flow in a rectangular flume with a raised invert (hump), calculated according to the BritishStandards Institute specification, BS-3680.

The transducer is mounted 65 cm (minimum 61 cm) above the highest liquid level.

The flume has a capacity if 0.11964 cubic meters per second at full head which is 50 cm.

Thus the distance from the transducer face to the zero-flow level is 65 cm plus 50 cm = 115 cm.

The flume characteristics are:

Maximum flowrate 0.11964 m3 /secondMaximum head 50 cmWidth of throat 20 cmWidth of approach channel 40 cmHeight of hump 15 cmLength of throat 100 cm

Water samples are to be taken every 1,000 cubic meters.The analog current output is to represent flowrate, and the display is to show the flow totalizer.

P0 = 0 Dimensions are in centimetersP1 = 1 Temperature is CelsiusP2 = 1 BS-3680 Rectangular FlumeU0 = 0.11964 Cubic meters (per sec) for 20 mA outputU1 = 0 Flowrate time units (per sec)U2 = 50 Full scale head in centimeters at 0.11964 m3/SU3 = 20 Width of throat in centimetersU4 = 40 Width of approach channel in centimetersU5 = 15 Hump height in centimeters (zero if no hump)U6 = 100 Length of throatP3 = 2 Display flow totalizer in run mode (F2)P4 = 115 *Distance from transducer to 0 flowrate head in cm.P5 = 0 Calculate flowrate for all heads(no low head cut off)P6 = 1 Fail safe highP7 = 60 Fail safe after 60 seconds without an echoP8 = 6 Sampler relay contact closure by flow volumeP9 = 1000 Contact closure every 1000 cubic metersP10 = 0 (relay deadband not applicable)P11 = 0 Analog output represents flowrateP12 = 20 Damping rate is 20 seconds for 100% change P13 = 1 Analog output is 0-20 mAP14 = 12 Optional logging-file site identification numberP15 = 1 Totalizer multiplier, one unit equals 1 cubic meter

Totalizer overflows every 96 days at full scale.

P16 to P18 not used on this example

* If AUTO ZERO Calibration routine (F12) is used, entry of the current liquid head will causeP4 = 115 to be deduced and entered automatically.

N.B. Data Logging occurs automatically and requires no specific set-up. However, the data logs will bemeaningless if the CLOCK and CALENDAR are not set to the present time and date. If data logs willnever be used the clock and calendar need not be set.

PL-269 9 – 3

EXAMPLE 3: VELOCITY-AREA PRODUCT

This example considers a trapezoidal irrigation channel in which flow is to be calculated by the product of thecross section of flow with the average flow velocity. The velocity sensor provides 4- 20 mA output with 20 mArepresenting a velocity of 400 cm/sec.

The velocity sensor output has been terminated by a 250 ohm resistor in order to suit the OCM II velocity inputwhich is 1- 5 volts.

NOTE: For velocity sensors with outputs other than 1- 5 V or 4 - 20 mA, refer to the information at the end ofthis example to re-scale the OCM II velocity input.

The channel has a base width of 2 metres, and the sides are constructed with a slope of 1:1.

The liquid is 1.0 metre deep at maximum capacity. The liquid velocity is expected to be 85 cm/sec at maximum capacity.

The transducer is mounted 70 cm (minimum 61 cm) above the highest liquid level.

The transducer to zero-flow level is thus 1.8 metres plus 70 cm which equals 250 cm.

The flow cross section at full capacity is given by:

A = h(b+mh) where h = head (liquid depth)b = base widthm = side slope (horizontal : vertical)(n.b.: m = 0 for a rectangular channel)

Hence the maximum area is 1.8(2 + (1 x 1.8)) = 6.84 square metres

The maximum flowrate is thus 6.84 square metres times 0.85 metres per second or 5.814 cubic metres persecond. This is the value to be entered as the calibration flowrate, U0, and is the value for which the OCM IIcurrent output will be 20 mA if the current is to represent flowrate.

The maximum output from the velocity sensor, 20 mA, occurs when the velocity is 400 cm/sec. This is the sensorcalibration velocity, vsensor, which must be entered as parameter U3.

The maximum liquid velocity, 85 cm/sec, is entered as parameter U4, vcal. This is the velocity for which the OCMII current output will be 20 mA if it is to represent the liquid velocity.

P0 = 0 Dimensions are in centimetresP1 = 1 Temperature is CelsiusP2 = 8 Calculate flow by velocity-area methodU0 = 5.814 Cubic metres (per sec) for 20 mA outputU1 = 0 Flowrate time units (per sec)U2 = 180 Full scale head in centimetres at 5.814 m3/SU3 = 400 Full scale velocity sensor in cm per secondU4 = 85 Maximum liquid velocity in cm per secondU5 = 200 Channel base width in centimetresU6 = 1 Channel side slope (0 horizontal : 1 vertical) P3 = 0 Display head in run mode ((F2) P4 = 250 *Distance from transducer to 0 flowrate head in cm.P5 = 0 Calculate flowrate for all heads (no low head cut off)P6 = 2 Fail safe lowP7 = 60 Fail safe after 60 seconds without an echoP8 = 3 Alarm on low liquid headP9 = 20 Alarm if liquid level below 20 centimetres P10 = 5 Cancel alarm if level raises 5 centimetres above 20

PL-269 9 – 4

P11 = 2 Analog output represents velocity (20 mA = 400 cm/sec)P12 = 20 Damping rate is 20 seconds for 100% change.P13 = 0 Analog output is 4-20 mA P14 = 5 Optional logging-file site identification numberP15 = 1000 Totalizer multiplier 1 unit = 1000 cubic metres

Totalizer overflows every 1990 days at full scale

P16 to P19 Not used in this example

* If AUTO ZERO calibration routine (F12) is used, entry of the current liquid head will cause P4 = 250 to be deduced and entered automatically.

N.B. Data Logging occurs automatically and requires no specific set-up. However, the data logs willbe meaningless if the CLOCK and CALENDAR are not set to the present time and date.

If data logs will never be used the clock and calendar need not be set.

PL-269 9 – 5

EXAMPLE 4: UNIVERSAL HEAD vs. FLOW CALCULATION

This example considers a type QV 306 Flume having a head-flowrate relationship as indicated by the graphbelow. You wish to have 50 L/S as full scale. Since 25 cm will give 51.18 L/S we will use this as a start point. Wethen divide the head measurements into 11breakpoints of 10 equal increments and extract the flow readings aslisted in the chart. If greater accuracy is required then the head can be divided into a maximum of 30 increments.

Breakpoint Head (cm) Flowrate (L/S) 0 0.0 0.00 1 2.5 1.47 2 5.0 4.12 3 7.5 7.94 4 10.0 12.24 5 12.5 18.24 6 15.0 23.35 7 17.5 30.00 8 20.0 36.47 9 22.5 43.83 10 25.0 51.18

You also want the totalization in cubic metres, output 4-20mA, all dimensions in cm, and you do not want theoutput to change if there is a fault such as a cut transducer cable.

91/02/14

Flowrate (Litres / Sec.)

50

5.0

A1

head(cm)

A2 A6A0

(AN in this case)

A7

302010 40

A8 A9 A10A4A3 A5

7.5

10.0

12.5

15.0

17.5

20.0

22.5

25.0

2.5

0

X = The Head at which the OCM II output of 20 mA is desired.

( E

qual

Incr

emen

ts )

PL-269 9 – 6

Enter the parameters as follows:

P0 = 0 Dimensions are in cm P1 = 0 Temperature is CelsiusP2 = 15 Unlisted Channel Head-Flowrate relationship U0 = 50.00 Design flow to produce 20 mA outputU1 = 0 Flowrate time units (per sec)U2 = 24.5 Head at design flow (U0) U3 = 10 Last A# used (AN) U4 = 25.0 Head at (AN)

(To access A parameters enter [A0] [E])

A0 = 0.0 flow 0A1 = 1.47 flow 1A2 = 4.12 flow 2A3 = 7.94 flow 3A4 = 12.24 flow 4A5 = 18.24 flow 5A6 = 23.53 flow 6A7 = 30.00 flow 7A8 = 36.47 flow 8A9 = 43.82 flow 9A10 = 51.18 flow 10

(To go to P parameters enter [P3] [E])

P3 = 1 Display flowrate in run mode (F2) P4 = 110 *Distance from transducer to 0 flowrate head in cm P5 = 0.5 Calculate at all flowrates over 0.5 cm of headP6 = 0 Fail-safe Hold (hold last reading until echo rcvd) P7 = 60 Fail-safe time out 60 seconds P8 = 6 Relay to be used for totalizer contact closureP9 = 1000 Contact closure for every cubic metre (1000 L) P10 = 0 Dead band not applicable P11 = 0 Analog output to be proportional to flow P12 = 90 Damping rate is 90 seconds for 100% changeP13 = 0 Analog output 4-20 mA P14 = 0 Optional logging-file identification number P15 = 1000 Totalizer display to be in cubic metres (1000L)

Totalizer overflows every 236 days at full scale flowrate

P16 to P18 not used in this example

* If AUTO ZERO calibration routine (F12) is used, entry of the current liquid head will cause P4 = 110 to be deduced and entered automatically.

N.B. Data Logging occurs automatically and requires no specific set-up. However, the data logs will bemeaningless if the CLOCK and CALENDAR are not set to the present time and date. If data logs will never be used the clock and calendar need not be set. However for trouble shooting it may be useful by noting when an abnormally high or low reading is occurring.

91/02/14PL-269 9 – 7

RE-SCALING VELOCITY SENSOR INPUT

The OCM II velocity sensor input can be re-scaled to accept input signals other than 1-5 volts. Its range ofadjustment allows re-scaling of any input signal with voltages ranging between 0 and 10 V, but of a minimumspan of 2.5 volts.

Care must be taken to avoid inadvertentlyadjusting the wrong zero or span potentiometer since there

are also zero and span adjustments associated with the temperature sensor and with the analog current output circuitry.

1. Measure the reference voltage at pin 8 of IC22, it will be about 2 volts. Record the exact value.

2. Remove the sealing compound from ZERO pot, P4 and SPAN pot, P2.

3. Turn the ZERO pot fully CCW (counterclockwise), 20 turns.

4. Connect 0 to 10 volt DC source to the input terminals, TB1-16 (+) and TB1-17 (-).

5. Adjust the input voltage until it is equal to the proposed input SPAN. (ie. 3 volts for a 7-10 volt velocity sensor input)

6. Adjust the SPAN pot, P2, until the voltage at IC33 pin 1 is exactly TWICE the voltage recorded in step 1.

7. Now adjust the input voltage to be equal to the SPAN (STEP 5) plus any OFFSET (e.g.: 3 volt SPAN plus 7 volt OFFSET = 10 volt for 7-10 volt velocity sensor input).

8. Then adjust the ZERO pot, P4, until the voltage at IC33 pin 1 is once again TWICE the voltage recorded in step 2.

9. Check that when the input voltage is adjusted through the desired input range, the voltage at IC33 pin 1 ranges from exactly zero to exactly twice the voltage recorded in step 1 (plus or minus 10 millivolts).

10. Record the new velocity input scaling and re-seal P2 and P4.

PL-269 9 – 8

APPENDIX C

SERIAL COMMUNICATIONS

The OCM II is equipped with serial communication capability. This feature gives the user computer-access to theOCM II‘s data log. It also provides access to the primary information gathered by the OCM II. The user mayestablish his own system of data logging using his own computer, printer and disk storage system or utilize thesoftware available from Milltronics and detailed in another instruction book. The auxiliary printer feature is detailedin Appendix D.

To assist the user who wishes to set up his own data logging system a special totalizer has been provided whichmay be read or cleared via the serial communications port. This allows a user to keep track of flow totals forperiods which may begin at a specific time of day other than midnight. This totalizer, D22, may be examined atany time via keypad selection, and may be preset or cleared via the keypad when in the ‘access‘ mode.

PROTOCOL

Serial communication rate selections are 300, 1200, 2400 and 9600 baud; 75, 150, 600, and 4800 baud are alsoavailable but require the installation of soldered jumpers. Protocol is 7-bit word, even parity, 1 stop bit.

A test facility is provided so that the user can verify that the serial port connections are wired correctly and thatcommunication baud rates have been properly selected. In this mode the user‘s computer transmits a messageto the OCM II which, in response, echoes the message back to the user‘s computer.

Communication is carried out in ASCII code. Every message to or from the OCM II begins with the ASCII startof text character, STX, which is represented by the hexadecimal number $02, and ends with an ASCII carriagereturn, hexadecimal number $0d.

It should be noted that the dollar sign is commonly used to represent a hexadecimal or base 16 number as in theprevious paragraph. It is also used in some computer languages, particularly BASIC, to signify a character or astring of characters. Thus there is a potential for confusion. This is especially so because the start of text characterand the carriage return which must frame a message are not formed by a single key stroke as are letters andnumbers. In BASIC for example they are represented by CHR$(number) where number is the DECIMAL numberrepresenting their respective position in the ASCII set. The following table may be useful.

CHARACTER ASCII HEX DECIMAL BASIC

Start of Text STX $02 2 CHR$(2) Carriage Return CR $0d 13 CHR$(13)

The OCM II will recognize request messages sent in either upper or lower case. Responses from the OCM II willnormally be a floating- point decimal number consisting of 6 digits plus a decimal point. Error messages sent bythe OCM II are in upper case. They consist of the letters ‘ERROR‘, a single space, and a single-digit numberwhich defines the type of error which has been encountered. (See ERROR MESSAGES below.) Thus, responsesfrom the OCM II will normally be an ASCII string of seven characters framed by the start of text character and acarriage return. (An exception is the diagnostic ECHO mode which simply returns whatever message is sent tothe OCM II as a string which may be up to 68 characters long.)

In every case the message sent to the OCM II contains three elements:

1 The start of text character 2 A message type identifier (one letter) 3 A carriage return

PL-269 9 – 9

In some cases the message must also contain a date. When this is the case it is placed immediately after themessage type identifier. It must be four digits long and in the form ddmm. For example 2301 would specify the23 rd of January.

The following example considers sending a request to the OCM II that it transmit its site identification number(entered as P14 during start up).

To retrieve the SITE NUMBER from the OCM II the user must transmit the following message:

STX; start of text = $02MT; message type = ‘s’ or ‘S’ CR; carriage return = $0d

In BASIC one might form a request string:

REQUEST$ = CHR$(2)+"S"+CHR$(13) and then print it to the communications port

The message returned by the OCM II will be an ASCII string representing the floating-point site number precededby STX and terminated by CR.

STX; start of text = $02 SITE #; 6 digits plus decimal, e.g. ‘15.0000’ CR; carriage return = $0d In BASIC one might receive the response with: INPUT (communications port), RESPONSE$ and then strip off the first and last characters

SITE$ = MID$(RESPONSE$,2,LEN(RESPONSE$)-1)

SUMMARY OF MESSAGE CODES

[Each must be preceded by STX ($02) and suffixed with CR ($0d)]

SEND TO OCM II OCM II RESPONSE

H returns the current head D0

R returns the current flowrate D1

P returns the primary totalizer rdg. D2

V returns the resetable totalizer rdg. D22

C clears the resetable totalizer D22

S returns the site identification number P14

Tddmm returns the daily flow total for a specific date from the file of logged data

Fddmm returns the 96 entries of the flowrate log (F9) for a specific date or for slower computers, use Lddmm

Lddmm sets up to return 96 entries of the flow-rate log (F9) for a specific date, one at a time in response to a prompt (N)

PL-269 9 – 10

N prompts for the next flowrate log entry (see above)

E test message simply returns the test message *

* NOTE: Any message longer than 68 characters will be ignored by the OCM II.

ERROR MESSAGES

The OCM II will return an error message in place of the requested data for any of four reasons:

a) If the message sent to the OCM II is incorrect, the OCM II will respond with ‘ERROR 1’.

b) If the requested data is not to be found in the OCM II’s data log, the OCM II will respond with ‘ERROR 2’.

c) If the 6-digit data in the OCM II‘s data log is a numeric overflow, the OCM II will respond with ‘ERROR 3’.

d) If the prompt message requesting the next flowrate entry is sent without first sending the message to set the single entry flow mode, or if more than 96 requests are sent for entries on a single day thenthe OCM II will respond with ‘ERROR 1’.

HARDWARE CONSIDERATIONS

Communication baud rate may be selected from 300, 1200, 2400 or 9600 by appropriate setting of the baud rateDIP switch located on the main circuit board. Baud rates of 75, 150, 600, and 4800 are also available by installationof soldered jumpers (refer to Installation section). Protocol is 7-bit word, even parity, with 1 stop bit.

All serial port designations are labeled with respect to the OCM II. That is to say, the TXD line is the OCM II’sTransmit Data output line and hence should be connected to the receiving devices RXD (Receive Data) line.

If handshaking is to be used then CTS, RTS and DCD lines must be connected according to the requirementsof the device.

PL-269 9 – 11

APPENDIX D

AUXILIARY PRINTER

The OCM II can be connected to a serial printer via the RS232 terminals and programmed to print at regularintervals. The choices are every minute or whole minute that will divide into 60 evenly, or every hour or wholehour that will divide into 24 evenly, or once a day (P17 & 18). Thus for interval of 15 minutes (P17 = 0; P18 = 15)the printout will be on the hour, 15 after, 30 after, and 45 after the hour. For an interval of 8 hours (P17 = 1; P18= 8) the print out will be at 00:00, 08:00 and 16:00 hours. When set for once per day the hour of the day can beset when to print. To print at 08:00 hours every day (P17 = 2; P18 = 8)

The output format is as follows:

Date 18/05/89 Time 09:12:00 Site Number 1.000000Head 24.86000 Velocity 12.26000 Temperature 17.10000 Flow Rate 2249.248 Flow Total 325468.9

Should there have been a power failure then the OCM II will output:

PRINTER READY18/05/89 09:15:00 (date and time power resumed)

Four seconds after power has returned.

The print output can be in English, French, German, or Italian. (P16 = 1, 2, 3, or 4 respectively, 0 = no print)

The output format is a string of ASCII characters terminated by a carriage return. A line feed is not sent. Theprinter must perform an automatic line feed upon receipt of the carriage return message. Lines are less than 40characters sent once every 2 seconds. Only upper case, lower case, numbers, and punctuation marks are used.

In the Run Mode ( F 2 ), an immediate printout may be obtained by pressing the "A" key on the OCM II keypad.

PL-269 9 – 12

APPENDIX E

GLOSSARY

Aeration: air gap between nappe and weir.

Beam angle: angle diametrically subtended by the one half power limits (-3dB) of the transducer‘s acoustic output.

Blanking: zone extending downward from the transducer face in which the received echoesare ignored.

Crest: the edge (sharp-crested weir) or surface (broad crested weir) over which the liquid passes.

Critical flow: see free flow.

Flume: a 3 part hydraulic structure, consisting of a converging, throat and diverging sections, to constrict the flow through the throat, thereby increasing the head in the converging section. The change in head is proportional to the change in flow.

Free flow: downstream liquid level is low enough or the discharge flow is fast enough, so as not to impede flow through the flume or weir.

Gauge well: see stilling well.

Head: liquid level above zero (static) reference level.

Maximum head: head at maximum flow.

Nappe: the jet of liquid leaving the weir crest.

OCM: open channel metering.

Primary measuring device: hydraulic structure of an open channel for measuring liquid flow. E.g. weirs and flumes.

Ringing: the inherent nature of the transducer to continue vibrating after the transmit pulsehas ceased. Ringing decays to acceptable levels in the order of milliseconds. Excessive cold and tightening of the transducer mounting (refer to figure 5) will increase the ring time, such that it may appear as an echo during the receive cycle.

Secondary measuring device: any instrument for measuring the head or flow related to the primary measuring device.

Stilling well: a well separate from but adjacent to the primary measuring device and interconnected by a small duct to provide an ideal point of measurement.

Subcritical flow: see submerged flow.

Submerged flow: when the downstream level rises or the discharge flow is so slow that it impedes the free flow of liquid through the primary measuring device.

PL-269 9 – 13

PL-269 9 – 14

CALIBRATION FLOW CHART

F0 [2.71828] Access Program Mode

P0 [ ] Dimension Units (0 = cm., 1 = in.)

P1 [ ] Temperature Units (0 = °C, 1 = °F)

P2 [ ] Primary Measuring Device, (Selected from Table 3)

If P2 = 0 If P2 ≠ 0

Enter required parameters selected from Table 4

U0 [ ] Max. Flowrate U0 [ ]

U1 [ ] Flowrate Units U1 [ ]

(0=/sec,1=/min,2=/hour, U2 [ ]

3=daily) U3 [ ]

U2 [ ] Max. Head U4 [ ]

U3 [ ] Exponent U5 [ ]

U6 [ ]

U7 [ ]

P3 [ ] Display Mode (0=Head,1=Flowrate,2=Total Flow)

P4 [ ] Distance to Zero Level (F12, auto zero may be used)

SIMPLE CALIBRATION COMPLETE, enter F5, F7 and F2; OR CONTINUE ADVANCED CALIBRATION

P5 [ ] Low Head Cutoff% (Flowrate=zero if below this % point)

P6 [ ] Failsafe Mode (0=Hold,1=High,2=Low)

P7 [ ] Failsafe Timer (Seconds from echo loss to Failsafe)

P8 [ ] Relay Function (0=none,1=High head alarm,2=High flow alarm,3=Low head alarm,

4=Low flow alarm,5=Time activated sampler-contact(min),

6=Flow activated sampler-contact (engineering units)

P9 [ ] Relay Setpoint (Desired relay activation value)

P10 [ ] Relay Deadband (% difference activate vs deactivate)

P11 [ ] Current Output Mode (0=Flowrate,1=Head,2= Velocity, 3=Fixed Maximum,4=Fixed Minimum)

P12 [ ] Current Output Damping (From .1 sec. to 600 sec.)

P13 [ ] Current Output Range (0=4-20mA, 1=0-20mA)

P14 [ ] Log Site # (Identifies data log information origin)

P15 [ ] Totalizer Multiplier (For totalizer vs display units)

P16 [ ] Auxiliary Printer Enable (0=None,1=English,2=French, 3=German,4=Italian)

P17 [ ] Print Interval Units (0=min,1=hours,2=daily)

P18 [ ] Print Start (Refer to Table 3)

F5 [ ] Current Time (## hours, ## minutes, 00 seconds)

F7 [ ] Current Date (## day, ## month, ## year)

F2 Calibration Complete (Enter run mode)

PL-269 9 – 15

F0= ACCESS CODE F6= SHOW DATE DO= HEAD

F2= RUN MODE *F7= SET DATE D1= FLOW

F4= SHOW TIME F9[E]+DDMM[E]= 15 min flow averages D3= TEMPERATURE

*F5= SET TIME F10[E]+DDMM[E]= Daily flow total D5= DISTANCE FROM FACE TO SURFACE

*F12[E]+CURRENT HEAD IN INCHES[E]= AUTO ZERO *ACCESS CODE F0 MUST BE ENTERED FIRST

Notes:

Weirs p must be a minimum of 2 times H max;M1 must be a minimum of 3 to 4 times H max;M4 approach must be straight for a minimum of 15 to 20 times H max;M5 must be a mimimum of 2 times H max;X is transducer locationThe surface must be smooth and flat at all flow rates.

Parshall Flume: M1 must be 2/3 of M3. M4 must be minimum of 10 times B

Palmer Bowlus Flume: M4 straight with no junctions for 25 times B.Slope continuous @ 2% max for small & 1% large size flumes;M1 = B/2; b = B/2; B = diameter of infeed pipe.

All percent errors to relate to full scale, i.e.: H max, Q max, and 20 mA. Totalizer relay energization may haveup to a 3 second delay before activating due to programming. Therefore, to determine the pulse rate aminimum time span of 3000 seconds must be used to reduce timing error to 0.1%. 300 seconds will give 1%resolution. For totalizer display calibration use all the digits shown so that there is at least 0.1% resolution inthe difference in counts from time 1 to time 2. Computer time delay for the totalizer display can be up to 1second, therefore, 1000 seconds is needed between time 1 and time 2 for 0.1% resolution. 100 seconds willgive 1% resolution.

M1B

M2

M4 M4

M2B

M1B

M2B

M2M1

M3

M4

M1

M4

b HmaxP4P4

HmaxHmax bb P4P4

Hmax

pp

Angle aM5 M5

V-Notch Weir Parshall Flume Palmer Bowlus orLeopold-Lagco Flume

Rectangular Notch Weir

SECTION X

FIGURES

LISTING

Figure

1 OCM II Outline Detail and Mounting 10 - 2

2 OCM II Layout 10 - 3

3 ST - 25 Transducer Outline & Wiring 10 - 4

4 Temperature Sensor Outline & Wiring 10 - 5

5 Transducer Mounting - OCM II Applications 10 - 6

6 Stilling Well Application 10 - 7

7 Applications with Standpipe 10 - 8

8 Wiring Formats - Basic Wiring 10 - 9- Optional Velocity Sensor- Isolated Analog Current Output

8A Wiring Formats - 24 V DC Power Option 10 - 10

8B Wiring Formats - Serial Communication 10 - 11- Auxiliary Device

9A&B OCM II Motherboard Schematic 10 - 12 & 13

10 OCM Transceiver & Display Schematic 10 - 14

PL-269 10 – 1

OCM II OUTLINE DETAIL AND MOUNTING

MODE READING

ACCESSRELAY

OCM

PEN

HANNEL

ONITOR

DISPLAYS & FUNCTIONS

DUCE

FPAR

369-

258.

1470

DISPLAYS & FUNCTIONS

ONITOR

HANNEL

PEN

MC

O

DUCE

FPAR

369-

258.

1470

RELAYACCESS

READINGMODE

375 mm(14.75")

4 mtg. holes8mm (.31") dia.

305 mm(12")

356 mm(14")

clearpolycarbonate

door

mtg holes 6.4 mm (0.25")@ 262 mm (10.3")x 306 mm (12.1")

194 mm(7.6")

324 mm(12.8")

OPEN STYLE

NEMA 4 ENCLOSURE

145 mm(5.7")

276 mm(10.9")

254 mm(10")

FIG. 1

PL-269 10 – 2

OCM II LAYOUT

C1 RP1A C5RP1 C6 TP1 TP2 TP3 RP3 RANGE

COUNTERCOMPUTER ADD.DATA & CONTROL

C27

C34

C35

C36

C38

C39

B2

BR1

1 GRN

2 BLK

3 WHT

4 BLK

5 WHT

SU1

T1

FU1 FUSEMDL SLOBLO

115VAC USE 1/4 AMP230VAC USE 1/8 AMP

ON

OFF

POWER

115/230 VAC 50/60HZ25VA

C50

REDYELRED

BRNBRN

BLUORGBLU

C51

678

910

111213

BR2

BR3

Q2 Q3B CE

R45

R46 D7R48

R58ZD3 R

47D8

R61

Q6Q5

EC52

R59 D10

ZD4

R60 C

53

D11

ZD5

TRANSDUCERHOT SHLD

ISOLATEDCURRENTOUTPUT

8 9

R30C44

D5Q4

R34A

ZD2

1ZERO

P1R31C40

C41

IC33

R3

R3

R3

5 6 7

D6

C45

SPAN2

P2

R32

3 4C42 CR3

C43

ZERO 2P4

SPAN 1P3

R38

J4

J5

J6

J7

75

150

600

4800

BAUD

ANALOGINPUT

C32 R27A

R27C

960024001200300

1234

BAUDRATERP5

93R R

40 OC1

R R R

42

43

44

OC2R41

47C 48

C

IC34

IC35

C49 RC2

123456

-15V+15V-6.2VNI-5

V

+24VI COMR

51

52R

SPANP5 53

R54R

ZEROP6 555657

RRR

D9

Q7Q8

B E

26R R

63

R64

R65

R66

54C C

55

56C

57C

76R

6ZD

36IC

IC37

58C

12D

13D

68R

LD1Q9

25 26 27 28 29 30

RL 1RELAYDRIVE

95

06

CRS 232

CO

M

TX

D

RT

S

DC

D

CT

S

RX

D

TB1

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

LIN

EL1 N

EU

TL2 G

R

115VAC

230VAC115VAC

CO

M

+24

V

SY

NC

HO

T

SH

LD

TRANSDUCERMAX LOAD15ma AVERAGE150ma PULSE MAX

O.C.M. II

RT

BLK

WHT

SH

LD

TEMPSENSOR

+ - SH

LD

SH

LD

-+

VELOCITYSENSOR

CURRENTOUTPUT

RELAY SHOWI INDE-ENERGIZEDPOSITION.250VAC5AMP.SEE INSTR.BOOK FOR COMPLETERATING.

INSTRUCTIONBOOK PL269SN10L1342

ML

K

K

P1BLANK

J7AGC

J9

J8A

GC

T1

J6 TUNING

BLANKJ5

J1COM

J2SYNC

J3ECHO

DUCE

FPAR

369-

258.

1470

FIG. 2

PL-269 10 – 3

ST-25 TRANSDUCER OUTLINE AND WIRING

NOTES: - Do not route cable openly in raceways

- Cable length: - standard: - 1m (3’)- optional: - consult Milltronics

- Radiating surface: - polyurethane

- Cable must be run in a grounded metal conduit with no other cabling (except temp. sensor cable). Ground shield only at OCM II. Insulate shield at junctions to prevent inadvertent grounding.

- Transducer wiring must be done in conjunction with approved conduit, boxes and fittings and to procedures in accordance with all governing regulations.

ST -25 transducer

11 12

11 12

120 mm(4.7")

1" NPT

black

whitehot

black

white shield

connection via customer’sjunction box

OR

direct connection

radiating surface84 mm(3.3") dia.

TB 1

TB 1

OCM II

cable

shield

RG62Ucoaxial cable

FIG. 3

PL-269 10 – 4

TEMPERATURE SENSOR OUTLINE & WIRING

NOTES:1. The temperature sensor should be mounted in a location which represents the temperature

fluctuations likely to occur between the transducer and the target.

2. To avoid false readings, mount the temperature sensor out of direct sunlight. Radiant heating can cause a differential of 20 °C between air and sensor temperature.

3. Temperature sensor cable can be run with the transducer cable in a grounded metal conduit. Ground shield only at OCM II. Insulate shield at junctions to prevent inadvertent grounding.

* 4. If a temperature sensor is used, the 9.53KΩ resistor must be removed from across terminals TB-1 13 & 14 .

5. Temperature sensor wiring must be done in conjunction with approved conduit, boxes and fittings and to procedures in accordance with all governing regulations.

FIG. 4

connection via customer’s junction box

OCM II *13 14 15

SHLD

WHT

BLK BLK

WHT

SHLD

BLK

WHT

SHLD

41 mm(1.63")

1" NPT

cable

59 mm(2.31")

PL-269 10 – 5

TRANSDUCER MOUNTING - OCM II APPLICATIONS

Bracketflexible conduit

* 1" NPT PVCcoupling

steel channel

ST-25transducer

Flexible conduit mounted transducer should not besubjected to wind, vibration or jarring.

Flexible Conduit

* 1" NPT PVC nipple

Blind Flange Plywood

* 1" NPTPVC coupling

Plywood mounting providesexcellent isolation, but must be rigidenough to avoid flexing if subjected

to loading.Flange, gasket and hardware supplied by customer.

Refer to Figure 7.

Guidelines:

1. Do not mount transducer directly to metal. Use PVC coupling and nipple as provided.

2. Do not overtighten mounting. Hand tightening PVC coupling and nipple is sufficient.

3. In OCM II applications, transducer mount (flange, bracket, conduit or plywood) must keep transducer perpendicular to liquid surface.

4. Transducer installation, whether in non-hazardous (as shown) or hazardous areas, must be done in conjunction with approved conduit, boxes and fittings and to procedures in accordance with all governing regulations.

5. Inner standpipe surface and ends must be smooth and free of burrs, ridges or seams. FIG. 5

PL-269 10 – 6

STILLING WELL APPLICATION

stand pipe

stilling well inlet

temperature sensor

transducer(refer to Figure 7) 60 cm (2ft)

minimum

max.head

standpipe inlet

primary measuring device

air vent

FIG. 6

blind flange

transducerface

stilling well

PL-269 10 – 7

APPLICATIONS WITH STANDPIPE

In some OCM II applications, access to the channel must be made via a standpipe. In such cases, thetransducer may be hung from a blind flange that will mate to the flanged standpipe.

The stand pipe length should be as short and the diameter as large as possible. As a rule of thumb, the -3 dB cone of the sound beam should not intersect the standpipe wall in applications opening into a largerarea. Otherwise, additional blanking will be required to compensate for the interference zone created by theopening (refer to section Appendices \ Troubleshooting).

sound beamintersectspipewall

reflection atinterferencezone created byopening

6 °

blanking extensionof 150mm (6") pastend of standpipemay be required no additional

blanking required

transducer radiatingsurface

no changein area

opening tolarger area

FIG. 7

PL-269 10 – 8

WIRING FORMATS

Basic Wiring

TB1

1L

N

242322212019181716151413121110987654321

DNGL

2COM

+24V

SYNC

HOT

SHLD

BLK

WHT

SHLD + -

SHLD + -

SHLD

RELAYCURRENTOUTPUT

VELOCITYSENSOR

230

115

115

TEMP.SENSOR

RT

TRANS-DUCER.

voltage selectjumper(s)

refer toFIG.4

refer toFIG. 3

power

TB1

N1L

DUCER.TRANS-

RT

SENSORTEMP.

115

115

230

SENSORVELOCITY

OUTPUTCURRENT

RELAY

DLHS

-+DLHS

-+DLHS

THW

KLB

DLHS

TOH

CNYS

V42+

MOC

2L G

ND

242322212019181716151413121110987654321

to sensor 15 mA Avg.150 mA Surge

(if required)

Velocity sensorsignal

Optional Velocity Sensor(additional to basic wiring)

L1

TB1

DUCER.TRANS-

RT

SENSORTEMP.

115

115

230

SENSORVELOCITY

OUTPUTCURRENT

RELAY

DLHS

-+DLHS

-+DLHS

THW

KLB

DLHS

TOH

CNYS

V42+

MOC

2L G

ND

242322212019181716151413121110987654321

N

to device

Isolated Analog Current Output(additional to basic wiring)

0-20 mA or 4-20 mA (P-13) into 750 ohm loadmaximum proportional to head, flow or velocity (P-11)

FIG. 8

PL-269 10 – 9

WIRING FORMATS (cont’d)

25 26 27 28 29 30

M D D S D SO X X T C TC T R R D C

RS232

1

2

3

4

5

6

RC2

TB1

FIG. 8B

ensure OCM II andexternal device areset at the sameBAUD RATE

refer to section Installation,Interconnection and Appendix CSerial Communications

Auxiliary Device (addtional to basic wiring)

supports optional auxiliaryMilltronics devices such as:

Satellite Dual Alarm,Satellite Pump Module

connect or disconnect auxiliarydevices only when the OCM IIpower is OFF. Ensure "Clipside"of the cable is mated to theclipside of the connector

DATA LINK

to serial port of external device

Serial Communication(additional to basic wiring)

PL-269 10 – 11

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