electric drive control systems (parameterization of ... 2.pdf · armature gating unit is used to...
TRANSCRIPT
Ministry of education and science of Russian Federation
Y.V. Plotnikov
ELECTRIC DRIVE CONTROL SYSTEMS (Parameterization of Thyristor Converters – SIMOREG DC
MASTER)
Electronic textbook
The textbook is intended for the Masters in the direction of 140 600 –
Electrical engineering, Electromechanics and electrotechnics of specialty
140 604 – “Electric drives and electric drive control systems”
Science editor: Associate Professor, Candidate of technical science N.D. Yasenev
Produced by “Electric drive and automatics of industrial plants” department
Methodological course book contains the detailed description of
methods and principles of parameterization of the thyristor converters
Simoreg DC master for direct current electric drives. The methodical
course book is intended for the “Electric Drive Control Systems”
discipline.
Methodical course book was composed according to the work
programme of profile – 140604 Electric drive and automation of
industrial plants and technological complexes. Methodological course
book is meant for Master of Science of full time education form.
Yekaterinburg
2012
2
CONTENTS
TABLE OF CONTENTS ............................................................................................ 2
INTRODUCTION ....................................................................................................... 3
1. GENERAL INFORMATION ABOUT SEMOREG CONVERTOR ................ 4
1.1. BRIEF DESCRIPTION OF CONTROL SYSTEM IN THE SIMOREG DC MASTER
CONVERTER ................................................................................................................. 4
1.2. USING THE BICO TECHNOLOGY IN THE SIMOREG DC MASTER CONVERTER
.................................................................................................................................... 7
2. PARAMETERIZATION OF SIMOREG DC MASTER .................................... 9
2.1 PARAMETERIZATION OF SIMOREG DC MASTER CONVERTOR WITH USING
SIMPLE OPERATOR CONTROL PANEL ............................................................................. 9
2.1.1 The LEDs assignment ......................................................................... 10
2.1.2 The buttons assignment ...................................................................... 10
2.1.3 Parameter types .................................................................................. 11
2.1.4 Parameterization example from simple operator control panel ........ 12
2.2 PARAMETERIZATION VIA THE SERIAL INTERFACE WITH USING THE DRIVE
MONITOR SOFTWARE ................................................................................................. 13
2.3 THE PARAMETERIZATION SEQUENCE OF SIMOREG DC MASTER CONVERTER
.................................................................................................................................. 17
2.3.1 Access level setting to the converter parameters and factory reset ... 17
2.3.2 Setting the rated converter voltage and current ................................ 17
2.3.3 Setting the motor rated data ............................................................... 18
2.3.4 The setting of speed sensor parameters ............................................. 19
2.3.5 The setting of armature current ramp-function generator ................ 20
2.3.6 The limitation of armature current and electromagnetic torque ....... 20
2.3.7 Parameterization of ramp-function generator ................................... 22
2.3.8 Automatic parameterization of armature current closed loop .......... 23
2.3.9 Automatic parameterization of speed closed loop ............................. 25
3. THE PARAMETERIZATION OF THYRISTOR CONVERTER FOR WORKING IN THE
PROFIBUS-DP NETWORK ........................................................................................ 28
3.1. Brief information about the PROFIBUS-DP ....................................... 28
3.2. The Simoreg DC Master convertor as a slave unit on the PROFIBUS31
3.3 Control and Status words and speed setpoint signal ............................ 34
3.4. The using of PKW mechanism for processing parameters .................. 39
3.5. The parameterization of Simoreg convertor for working from
PROFIBUS-DP ...................................................................................................... 43
3. THE PLOTTING OF TRANSIENTS OSCILLOGRAMS WITH USING THE
DRIVE MONITOR SOFTWARE ........................................................................... 45
GLOSSARY ............................................................................................................... 50
REFERENCES .......................................................................................................... 55
3
INTRODUCTION
Nowadays the Microprocessor-Based Converters are widely used in the
different electric drive systems and technological complexes. Despite of some
disadvantages (the maintenance requirements, low power factor, low reliability of DC
motor etc.), compare to the alternating current electric drive these systems have some
advantages, such as:
low coast four quadrant operation;
continuous duty at low speeds with full electromagnetic torque;
high starting torque;
wide speed range for constant power;
minimal space requirements.
The adjusting of microprocessor control system in the thyristor convertor is
made by means of parameters, which are responsible for some special functions of
control system. Often, the special software is used to vary the convertors parameters
and to monitor the electric drive state.
Therefore the practical skills of parameterization of microprocessor control
systems of thyristor converters is a one of most important skills of modern engineers.
The Simoreg DC Master convertors are the part of Siemens automation
technologies. The Simoreg converts family is available for wide power range from
6.3 to 2500 kW. It has a wide range of different functions, which are widely used on
practice. The availability of digital and analog inputs/outputs and network connection
allow user to connect converter to the external control systems and sensors.
The main feature of Simoreg DC Master Convertor is that it allow user to
modify its own control system by means of BICO technology. It means that closed-
loop control functions are implemented in the software as program modules that are
“wired up” via parameters.
The Simoreg DC Master with communication board can also be used as a slave
unit in the different industrial networks, such as PROFIBUS. And in the Simoreg
4
converter it is possible to set parameters from the programmable logic controller by
means of PROFIBUS network.
This methodological course book contains detailed description of methods and
principles of parameterization the microprocessor control system in the thyristor
converters Simoreg DC master for direct current electric drives. The methodological
course book is belonged to the “Electric Drive Control Systems” discipline.
1. GENERAL INFORMATION ABOUT SEMOREG CONVERTOR
1.1. Brief description of control system in the Simoreg DC Master
Converter
The functional diagram of control system, which is used in the Simoreg DC
Master converter, is shown on the figure 1 [5]. This control system is based on the
subordinate control principles. In the armature circuit control system consists of inner
armature current closed loop and outer speed closed loop. In the current control
system the armature precontrol is used to increase the performance of current loop in
the interrupted current mode of thyristor converter. That is in the current closed loop
the technical linearization of plant in the interrupted current mode is used.
Armature gating unit is used to produce the control angle of thyristor convertor
from the control voltage signal and to limit the control angel on the acceptable levels.
Also in this functional block the current direction is selected.
To protect motor from overload conditions the current and torque limitation
blocks are used.
The P or PI speed controller can be used in the automatic speed control system.
The selection of controller type is produced by means of some parameters, which are
described in detail below. It is also possible to set additional filters both in the speed
and current closed loops. The actual speed signal comes from the speed sensor. The
different speed sensor can be used in this control system from different encoder to
analog tachogenerators. It is also possible to build sensorless speed control system.
5
The speed limitation block protects motor from the speed exceeding and is set
on the input of the speed control system.
The ramp-function generator (RFG) allows to limit the dynamic motor torque
in the transient mode of electric drive. In this system both the second order RFG and
the first order RFG can be used. The selection of RFG type is produced by means of
serial parameters. Other parameters set an acceleration and deceleration time of
electric drive.
The control system in the field circuit consists of inner field current closed
loop and outer electro-motive force (EMF) closed loop. In the both loops the
precontrol technology is used to increase the performance of control system.
The field current limitation is used to protect field circuit from the high field
current. This nonlinear element allows to flow field current only in positive direction.
The proportional-integral EMF controller is used to compensate the persistence
in the EMF calculation circuit. The actual EMF value is calculated based on the
armature current and voltage signals. Than calculated EMF signal flows through the
nonlinear element with module characteristic.
6
Fig
. 1. S
impli
fied
funct
ional
dia
gra
m o
f co
ntr
ol
syst
em i
n t
he
SE
MO
RE
G D
C M
aste
r C
onver
ter
7
1.2. Using the BICO technology in the Simoreg DC Master converter
The connectors and binectors are the basis of BICO technology (BInector
COnnector), which is used to connect the different functional blocks each other and
to build the different control systems. The inputs and outputs of each functional block
are available in the form of connectors. To put in other words, connector is a 16 or 32
(double-word connector) bit signal of some functional block. Connectors have a
value range of –200 % to +199.99 %. The connections between individual function
blocks can be selected by means of convertor parameters.
The binector is a logic value and can be equal 0 or 1. For example, some
binector is used as a start “button” of electric drive, while the some connector is used
as a speed setpoint value.
There are many different freely assignable function blocks in the Simoreg DC
Master convertor such as:
fault and alarm message triggers;
connector / binector converters;
mathematical functions (adders, substractors, switchable sign inverters,
multipliers, dividers, absolute-value generators etc.);
limiters and limit-value monitors;
processing of connectors (maximum and minimum selectors, averagers,
tracking and storage elements etc.);
position deviation acquisition and root extractor;
control elements (integrators, derivative and delay elements,
technological controllers etc.);
ramp-function generators;
counters;
logical functions (and, or, exclusive or, decoders and demultiplexers,
inverters, RS flipflops, timers etc.).
These functional blocks allow user to realize the complex automatic control
system of electric drive. The connectors and binectors also allow to modify existing
control system according to the special electric drive requirement.
8
The control system structure of Simoreg convertor is presented in view of
functional diagram in the operating instruction [5]. The description of different
elements on the Simoreg functional diagrams are shown in the table 1.
Table 1
Description of main elements for BICO structure
Indication Description
1 2
Binector – is a logical signal, which may have two value 0 or 1. The binector
is used to send and receive logical signals both in the inner circuit of
convertor and external signals from other devices. Writing form: В ХХХХ,
where ХХХХ – binector number.
Connector – 16 or 32 bit signal, which is formed in the converter program or
converted from the analog signal.
There are two connector types:
К ХХХХ – 16 bit connector;
КК ХХХХ – 32 bit connector;
where ХХХХ – connector number.
Hard connected binector (selection is not possible)
Hard connected connector (selection is not possible)
The binector selection. In the brackets the factory setting is shown. The values
range is all binector numbers.
The binector selection with using index parameter. In the brackets the factory
setting is shown. The values range is all binector numbers. It is possible to
select one of connected binectors by means of parameter index. Parameter
index is selected via control words.
Selection of one binector from factory ones with index parameter.
Connector selection. In the brackets the factory setting is shown. The values
range is all connector numbers.
The connector selection with using index parameter. In the brackets the
factory setting is shown. The values range is all connector numbers. It is
possible to select one of connected connectors by means of parameter index.
Parameter index is selected via control words.
9
Table 1. Continuation
1 2
The connector selection with using index parameter. In the brackets the
factory setting is shown. The values range is all connector numbers. It is
possible to select one of connected connectors by means of parameter index.
Parameter index is selected via control words.
Selection of one from factory connector with index parameter.
Link to the 152 page of functional diagram.
2. PARAMETERIZATION OF SIMOREG DC MASTER
2.1 Parameterization of Simoreg DC Master Convertor with using simple
operator control panel
The simple operator control panel (PMU – Parameterization Unit) is a part of
Simoreg DC Master Converter and consist of display, three status LEDs and three
keys (fig. 2). This panel is mounted on the convertor face and allows user to adjust all
parameters and select the structure of microprocessor control system. The parameter
value and number is shown on the 5-digit segment display. The three LEDs are used
to estimate the status of thyristor convertor. For example, the Ready LED shows that
the electric drive, which is powered from thyristor convertor, is ready to run.
Fig. 2. Simple operator control panel
The description of LEDs and control panel buttons is shown below.
10
2.1.1 The LEDs assignment
Run – green LED is illuminated during the normal work (without errors) of
electric drive with set electromagnetic torque direction. The state of electric drive can
be displayed in the r000 parameter.
Ready – yellow LED is illuminated during the electric drive is in ready to run
state. (o1 – o7 – parameter r000).
Fault – red LED is continuously illuminated whet the some error of electric
drive is occurred during the work or parameterization process. The error number is
indicated on the panel display. And LED is flashed during the alarm mode of electric
drive and warns user about the invalid mode of thyristor convertor.
2.1.2 The buttons assignment
The buttons assignment on the simple operator control panel is shown in the
table 2.
Table 2
The PMU buttons assignment
Button Assignment
Switches between parameter number, parameter values and index number of
indexed parameters.
Acknowledges the active fault messages (fault reset).
Simultaneous pressing P and UP keys will lead to switch the active fault
message to the background.
Simultaneous pressing P and DOWN keys will lead to switch the active fault
message to the foreground display on the PMU.
Selects the higher parameter number in the parameterization mode. When the
highest parameter number is reached, the pressing the key returns to the other
end of parameters number range.
Increases the selected and displayed parameter value in value mode.
Increases the parameter index in index mode (for indexed parameters).
Accelerates an adjustment process activated with the DOWN key (if both keys
are pressed at the same time).
Selects a lower parameter number in parameter mode. When the lowest number
is displayed, the key can be pressed again to return to the other end of the
number range (i.e. the lowest number is thus adjacent to the highest number).
Decreases the selected and displayed parameter value in value mode.
Decreases the parameter index in index mode (for indexed parameters).
Accelerates an adjustment process activated with the UP key (if both keys are
pressed at the same time).
11
2.1.3 Parameter types
The main parameters of Simoreg convertor are displayed on the PMU as a P, r,
U and n. Parameters for an optional supplementary board are called H, d, L or c
parameters. The parameters list can be divided in to three main groups:
Display parameters (r) are used to display the current values of controlled
variables, such as speed setpoint, actual speed, actual voltage, armature current
setpoint, armature current, etc. The values of display parameters are read-only values
and cannot be changed. The most important display parameters are shown in the
table 3.
Table 3
The display parameters description (selectively)
Parameter
number Parameter description Value range
r000
Operating status display (selectively):
o1.x – waiting for operating mode.
o2.x – wait for setpoint.
o3.x – test mode.
o4.x – waiting for armature voltage.
o5.x – waiting for field current.
o6.x – wait status before the line contactor is closed.
o7.x – wait for switch-on command (o7.0 – waiting switch-
on from the terminal, o7.1 waiting switch-on via binector).
o8.x – waiting for acknowledgement of starting lockout.
o9.x – fast stop (OFF3).
o10.x – voltage disconnection (OFF2).
o11.x – fault.
o1.x – o15.x
r001 Motor speed setpoint (terminals 4 and 5) from – 200 to 199,99 %
r002 Actual motor speed (terminals 103 and 104) from – 200 to 199,99 %
r019 Armature current value from – 200 to 199,99 %
[% from P100]
r021 Electromagnetic torque setpoint after limitation from – 200 to 199,99 %
r023 Difference between the speed setpoint and actual speed
(speed error)
from – 200 to 199,99 %
r027 Display of ramp-function generator output from – 200 to 199,99 %
r037 Actual value of motor electro-motive force от – 1500 до 1500 V
r038 Armature voltage value от – 1500 до 1500 V
12
Besides, by means of parameters P042, P044 and P046 in the parameters r041,
r043 and r045 on the indication the values of different binectrors and connectors can
be displayed.
For example, the setting P042=K0142 (K0142 – motor electromagnetic torque
in percent) means that the in the parameter r041 the motor torque will be displayed.
Setting parameters (P, U, n) are used to display and change converter
parameters such as the rated motor current, thermal motor time constant, speed
controller P gain, etc. These parameters are used to adjust the microprocessor control
system in the thyristor convertor before the electric drive running.
Indexed parameters (P, U, n) are used to both display and change several
parameter values which are all assigned to the same parameter number. It means that
some parameters of convertor have a number of different values, which are located in
the different parameter indexes. The parameter index can be changed during the
electric drive work. It allows users to change the control system setting depending of
different working conditions of electric drive.
2.1.4 Parameterization example from simple operator control panel
Let’s consider the changing of starting time P303 from factory setting
P303=10 sec to the value 5 sec:
1. To reach the parameter number from the operational display state (o7.0 see
table 1), press the P key and then the Up or Down key to select parameter number
P303.
2. To reach the parameter index level from the parameter number level, press P
and then the Up or Down key to select individual index in00. If you press P when a
non-indexed parameter is displayed, you go directly to the parameter value.
3. To reach the parameter value P303 from the parameter index level press P
button one more time.
4. By pressing the Up or Down keys, set the parameter value P303=5 sec and
press P button to acknowledge the setting parameter value.
13
2.2 Parameterization via the serial interface with using the Drive Monitor
Software
The parameterization examples will be considered on the laboratory setup,
which was described in detail in the methodological course book for laboratory
work [4].
Before the laboratory setup will be powered it is necessary to connect the
thyristor converter to the personal computer by means of special cable. Then, the
power convertor is switched on, and after that the personal computer is switched on.
The Drive Monitor Software allows users to adjust the parameterization of
microprocessor control system in the converter and to plot the transients in the
electric drive.
At first it is necessary to choose the new parameter set with factory
settings (fig .3).
Fig. 3. New parameter set in the Drive monitor window
Then, in the Drive properties windows it is necessary to select the Drive type –
Simoreg DC Master and point the software version 02.0 (fig. 4). The remainder
parameters are selected according to the figure 4.
Then it is necessary to replace the existing file SIMOREG DC
MASTER_tmp.dnl with factory settings. After that, the parameters list with factory
setting is appeared. Connection between the thyristor converter and PC is set by mean
of key Online RAM on the control panel of Drive monitor software.
In the case of successful connection, in the device status line the message
Connection with device OK will be appeared. The main window of Drive monitor
Software is shown on the fig. 4.
14
Fig. 4. The Drive Properties window
If the connection PC with device is not set, it is necessary to check the Online
Setting in the menu Tools. At first, it is recommended to select another COM port
number (see fig. 6).
Attention! The Online Setting parameters are changed only after the restarting
of Drive monitor program.
In the Drive Monitor Software the parameters are changed by means of dialog
boxes, in which the parameter values are set or selected from the parameter list. In the
left part of program, the parameter tree is situated, which is used to group the
parameters of converter according to the functional destination (see fig. 5).
15
Fig. 5. Main window of Drive Monitor Software
Fig. 6. Connection convertor with PC windows
16
Assignment of main buttons on the control panel of Drive Monitor (see fig. 5):
– Online-RAM is used to connect the PC with RAM (Random Access
Memory) memory of thyristor converter.
– Online-EEPROM is used to connect the PC with EEPROM (Erasable
Programmable Read-Only Memory) memory of thyristor converter.
– Parameter list complete is used to show the full parameter list.
– Free Parameterization is used to switch in the free parameterization
mode. In this mode, at first, the parameter number is entered, and after that the
parameter value is set.
– Parameterization guide launches the convertor parameterization wizard
for quick taking into operation the thyristor converter.
– Online settings are used to set connection parameters between the
convertor and PC.
– Trace launches the transients building mode for direct current electric
drive.
– Download RAM – downloads user parameter from file to RAM memory
of thyristor converter.
– Download EEPROM downloads user parameter from file to EEPROM
memory of thyristor converter.
– Upload base unit – uploads the all parameters from the convertor to file.
– Upload base unit (only changes) – uploads the parameters, which are
different from factory setting, from the convertor to file.
The other buttons assignment is intuitively obvious for users.
In the lower part of the Drive monitor program, the start and stop
buttons, speed setpoint field Setpoint [%] (when the electric drive is controlled from
the program) and actual speed field Act. Val [%] are situated.
17
2.3 The parameterization sequence of Simoreg DC Master Converter
For example, let’s consider the parameterization of Simoreg DC Master
Converter. The rated motor data and the laboratory setup description were considered
in the first part of methodological course book for laboratory work [4].
After the convertor was powered, on the PMU display the current state of
thyristor convertor will be displayed (for example o7.0). The state of Simoreg
convertor is depicted in the r000 parameter (see table 2). The parameterization of
microprocessor control system of thyristor convertor is carried out in the following
sequence.
2.3.1 Access level setting to the converter parameters and factory reset
1. If the parameter setting is made in the first time or it is unknown the initial
convertor state, it is recommended to reset the all parameters to factory setting. The
setting of parameter P051 = 21 will leads to factory reset of converter parameters.
After this setting, the restoring of parameter values to default and performing the
initial converter offset adjustment will be executed. Then, parameter P051 is
automatically set in the initial value P051=40.
2. Set parameter P051 = 40 [Key parameters]. This value allow user to modify
all parameters of thyristor converter.
3. Set parameter P052 = 2 [Selection of display parameters]. This setting
allows to display all parameters on the simple operator panel (PMU).
2.3.2 Setting the rated converter voltage and current
1. Set parameter Р076.001 = 33,3 % [Reduction of converter rated DC current
(armature)] in the index 001. The value 33 % provides the decreasing of rated
converter DC current according to the motor rated current. This parameter is used for
the purpose of achieving a close match between the converter and motor, the
converter rated DC current is reduced to the value entered here.
2. Set parameter value Р076.002 = 20 % [Reduction of converter rated DC
current (field)] in the index 002. The rated current of field circuit is 20 % of rated
convertor field current [4].
18
Note: For thyristor convertors, which have a rated power higher that motor
rated power, the following parameter values can be set in the P076: 10, 20, 33,3, 40,
50, 60, 66,6, 70, 80, 90 %.
3. Set the parameter Р078.001 = 400 V [Rated input voltage converter
armature]. This is a rated voltage of on the input thyristor converter in the armature
circuit.
4. Set the parameter Р078.002 = 400 V [Rated input voltage converter field].
This is a rated voltage of on the input thyristor converter in the field circuit.
The rated voltage values of the power system actually used to supply the power
section must be set in this parameters P078.001 (2).
2.3.3 Setting the motor rated data
1. Set parameter Р081 = 0 [EMF-dependent field weakening]. This setting is
used for control system without field-weakening mode. The rated field current is
continuously applied to the field circuit.
2. Set parameter Р100 = 4,5 А [Rated motor armature current]. The rated
armature current is set according to the motor rating plate.
3. Set parameter Р101 = 220 V [Rated motor armature voltage]. The rated
armature voltage is set according to the motor rating plate. The one of the functions
of this parameter is to determine the point at which the field-weakening mode is
started.
4. Set parameter Р102 = 0,29 А [Rated motor field current]. The rated
excitation current is set according to the motor rating plate.
5. Set parameter Р103 = 0,25 А [Minimum motor field current]. The parameter
value P103 should be less than 0,5∙Р102 to execute the optimization run for field
weakening mode. In this example it is not supposed that we will work in the field
weakening mode.
6. Set parameter Р109 = 0 [Control word for speed-dependent current
limitation]. 0 – Speed-dependent current limitation is deactivated. 1 – Speed-
dependent current limitation is activated. The setting P109=1 is used in the two-
19
region speed control systems to reduce the maximal armature current in the field
weakening mode.
7. Set parameter Р114 = 10 minutes [Thermal time constant of motor]. This
parameter is used to protect motor from overload current in the steady-state mode.
The value Р114 = 0 means that the I2t protection is deactivated.
The motor parameters such as: P110 [Armature circuit resistance], P111
[Armature circuit inductance], P112 [Field circuit resistance], P115 [EMF at
maximum speed in operation without tachometer], P118 [Rated EMF value] and
P119 [Rated speed] are set automatically during the current controller optimization
procedure P051=25.
2.3.4 The setting of speed sensor parameters
1. Set parameter Р083 = 1 [Selection of actual speed value]. The value of this
parameter is selected according to the following:
0 – Actual speed value is not selected;
1 – Actual speed value comes from the analog tachogenerator, which is
connected to the terminals XT.103, XT.104);
2 – Operation without tachogenerator (Closed EMF loop is used);
3 – Actual speed value is wired up freely (selected in P609).
Signal from the analog tachogenerator is displayed in the parameter r002.
2. Set parameter Р741 = 30 V [Normalization for “Main actual value”]. This
value sets the rated voltage on the output of speed sensor under the rated motor
speed. Maximum value is 270 V.
3. Set parameters P671= 1 [Source for control word 1, bit11] and P672= 1
[Source for control word 1, bit12]. The values 1 are set for bidirectional electric
drive. 0 – positive (P671) or negative (P672) direction of rotation is disabled.
4. Set the sign of speed signal P743= 0 [Mode of signal injection at “Main
actual value” analog input]. The following values are used in parameter P743:
0 – Injection of signal with sign;
1 – Injection of absolute value of signal;
20
2 – Injection of signal with sign, inverted;
3 – Injection of absolute value of signal, inverted.
The sitting P743=1 is used for non-bidirectional electric drives. The sign of
actual speed can be changed by means of setting Р743= 2.
2.3.5 The setting of armature current ramp-function generator
To limit the rate of armature current the ramp-function generator on the input
of current closed loop is set by means of following parameters (see fig. 9):
1. Set parameter P157= 1 [Control word for current setpoint integrator]. Value
1 means that the ramp-function generator (RFG) acts in the current setpoint cannel.
The 0 value means that the RFG is active only after the change of torque direction.
2. Set parameter P158= 0,01 sec. [Ramp-up time for current setpoint
integrator]. The recommended value for older DC motors, which is not suitable for
high current rates, is 0,04 sec.
These two parameters allow to reduce the gearbox stressing and to protect DC
motor from high armature current rates.
2.3.6 The limitation of armature current and electromagnetic torque
The simplified functional diagram of torque limitation is shown on the figure 6
[5]. As can be seen from figure 7 the level of torque limitation (K0143, K0144) can
be varied depending of different parameters. By means of P169 parameter the torque
or current limitation is selected. The normalization of current limits (P170, P171) by
means of P100 (Rated armature current) parameter is realized. From index
parameters P605 and P606 comes the constant value 200 and -200 %
correspondingly. Then, from current (P170, P171) and torque (P180, P181)
limitations the minimal for positive torque direction or maximal for negative torque
direction value is selected and comes to the nonlinear element with saturation
characteristic. The binectors B0202 and B0203 set a unity value, when torque
setpoint will reach positive or negative limits.
21
Fig. 7. Torque limitation in the Simoreg DC Master converter
1. Set parameter P169 = 1 [Select closed-loop torque / current control]. In this
case the closed-loop current control with torque limitation is used. The torque
limitation is a function of motor magnetic flux. In the one-region speed control
system the torque limitation will corresponds to armature current limitation.
2. Set parameter P170 = 0 [Select closed-loop torque / current control]. The
combination of P169 and P170 parameters set the torque or current limitation. In this
case the motor torque limitation is used. The combination P169= 0 and P170= 0 set
the armature current limitation and combination P169= 0 and P170= 1 set closed-loop
torque control with torque limitation.
22
3. Set parameter P171= 150 % [System current limit in torque direction I]. The
parameter value sets the armature current limitation in the positive torque direction.
This value is selected according to the rated motor and thyristor convertor data. The
150 % means that the maximal armature current will not exceed the value 1,5 P100
A. Where, P100 parameter is the rated motor current.
4. Set parameter P172= -150 % [System current limit in torque direction II].
The parameter value sets the armature current limitation in the negative torque
direction.
5. Set parameter P180= 150 % [Positive torque limit 1]. This parameter is used
to limit the motor torque value in the positive torque direction. The value is selected
according to the motor and thyristor convertor rated overload current. The 150 %
means that the maximal electromagnetic torque will not exceed the value 1,5 Mn.
Where, Mn is the rated motor torque.
6. Set parameter P181= -150 % [Negative torque limit 1]. This parameter is
used to limit the motor torque value in the negative torque direction.
One should add, that these parameters can be used to implement the
nonreversible electric drive. For example, if we sets the parameter value P171= 0 %
we don’t allow electric drive to rotate in the positive direction.
2.3.7 Parameterization of ramp-function generator
The simplified functional diagram of ramp-function generator (RFG) in the
Simoreg DC Master is shown on the figure 8.
The main parameters of first order ramp function generator are P303 – Ramp-
up time 1 and P304 – Ramp-down time 1. The second order RFG is realized by
setting the not zero values for parameters P305 – Lower transition rounding 1 and
P306 – Upper transition rounding 1. The parameter P330 is used to set time of RFG in
seconds (0) or in minutes (1). The parameters P307–P314 are used in some cases,
where is it necessary to switch the rete of RFG during the work of electric drive.
Index parameter P636 can be used to vary the rate of RFG depending on some
connecter value. The default values in all indexes of P636 parameters are 100 %.
23
Fig. 8. Ramp function generator in the Simoreg DC Master converter
1. Set parameter P303= 10 sec [Ramp-up time 1]. The value 10 means, that
electric drive will accelerate from zero to rated motor speed at 10 seconds.
2. Set parameter P304= 10 sec [Ramp-down time 1]. The value 10 means, that
electric drive will decelerate from rated to zero motor speed at 10 seconds.
3. Set parameters P305= P306= 0 sec [Lower and Upper transition rounding 1].
The first order ramp-function generator is used.
The ramp-up and ramp-down time of RFG is selected from the maximum
acceptable value of dynamic torque during the transients.
2.3.8 Automatic parameterization of armature current closed loop
The simplified functional diagram of armature current controller in the
Simoreg DC Master is shown on the figure 9.
24
Fig. 9. Armature current controller in the Simoreg DC Master converter
On the figure 9, the armature current precontrol is used to improve the
performance of current closed loop in the interrupted current mode of thyristor
converter. The gain kcc and time constant Tcc of armature current controller are set in
the parameters P155 and P156. The parameters P176 and P175 are used to vary the
gain and time constant of current controller depending on some external conditions.
Parameters P164 and P154 deactivate the Proportional (P) and Integral (I)
components of current controller.
The main parameters of armature current closed loop such as gain and time
constant of current controller are adjusted during the current loop optimization
procedure (P051=25).
In order to make the current controller optimization it is necessary:
1. To make sure the thyristor convertor is in the ready to run operating state
o7.0 or o7.1, and there are no any errors and alarms on the display on PMU.
2. Set parameter P051=25 [Key parameters – Optimization run for precontrol
and current controller (armature and field)]. After that, the converter switches to
operating state o7.4 for several seconds and then to o7.0 or o7.1 and waits for the
25
input of switch-on and operating enable. The flashing of the decimal point in the
operational status display on the PMU indicates that an optimization run will be
performed after the switch-on command.
3. By means of switches SA6 and SA5 give commands for operation enable
and switch-on. As soon as the converter reaches operating status o1.0, the
optimization run is executed. The current controller optimization procedure will lasts
approximately 40 seconds. The following parameters are set automatically during the
optimization procedure: P110 [Armature circuit resistance], P111 [Armature circuit
inductance], P112 [Field circuit resistance], P155 [Armature current controller P
gain], P156 [Armature current controller reset time], P255 [Field current controller P
gain], P256 [Field current controller reset time], P826 [Correction of natural
commutation timing].
Attention! One must note, that if the switch-on command is not given within 30
s, this waiting status is terminated and fault message F052 displayed.
After the optimization procedure the parameter P051 will be returned in the
initial state P051=40 and the field current will be decreased to zero. Then, switch-off
the SA5 and SA6 tumblers to the initial position.
2.3.9 Automatic parameterization of speed closed loop
The simplified functional diagram of speed controller in the Simoreg DC
Master is shown on the figure 10.
The speed controller gain ksc and time constant Tsc are set in parameters P225
and P226. The time constants of speed setpoint and feedback filters are set in
parameters P228 and P200.
26
Fig
. 10. S
pee
d c
ontr
oll
er i
n t
he
Sim
ore
g D
C M
aste
r co
nver
ter
27
The nonlinear element with inputs P553 and P554 are used to adapt the speed
controller gain and time constant to changed external conditions. The speed feedback
signal can be selected from five different sources by means the P083 parameter. Also
in the speed closed loop there are parameters which are responsible to stop or set the
I-component of speed controller in some cases (P696, P695). The parameter P224 can
be used to switch-off the integral component of speed controller and build the single-
integration automatic speed control system (P224= 0). The parameter P236 sets the
performance of speed control closed loop.
The main parameters of speed closed loop such as gain and time constant of
speed controller are adjusted during the speed loop optimization procedure (P051= 26).
To run the speed controller optimization it is necessary:
1. Set parameter P051= 26 [Key parameters - Optimization run for speed
controller]. Then, by means of switches SA6 and SA5 give commands for operation
enable and switch-on as in the privies chapter. The optimization process will display
on the PMU by means of flashing the different numbers.
During the speed controller optimization, the motor is accelerated at a
maximum of 45 % of its rated armature current. The motor may reach speeds of up to
approximately 20 % of maximum speed. The following parameters are set
automatically during the optimization procedure: P225 [Speed controller P gain],
P226 [Speed controller reset time] and P228 [Filter time for speed setpoint].
After the optimization procedure the parameter P051 will be returned in the
initial state P051=40 and the field current will be decreased to zero.
2. Then, switch-off the SA5 and SA6 tumblers to the initial position.
Note: The speed controller optimization run takes into account the filter of the
actual speed controller value parameterized in P200. To achieve the optimum
response of speed closed loop the parameter P228 is equal to P226.
3. Check the value of motor maximum speed. If the maximum speed was
changed during the optimization procedure more than 10 %, it is necessary to correct
the speed sensor gain in the parameter P741 (for analog tachogenerator). Then, the
speed loop optimization procedure should be repeated.
28
Note: The automatic parameterization of speed and current closed loop
provides the acceptable but often not optimal transients in the speed and current
control system. To adjust the optimal responses in the speed and current closed loops,
the manual correction the of speed and current controller parameters with using
oscilloscope is necessary.
4. Then, it is necessary to check the work of electric drive. Set the switches
SA6 and SA5 to upper position and set the speed setpoint 1000 rpm be means of
RP2 potentiometer. Then, to reverse the electric drive it is necessary to set the switch
SA7 to upper position. To stop direct current electric drive the SA5 switch is used.
The starting of electric drive and setting of speed setpoint value can be also
realized by means of Drive Monitor Software. In order to start drive from the
program, it is necessary to set the parameters P433= K2002 [Source for standard
setpoint] and P654= K2100 [Source for control word 1, bit0]. During the work from
software, the switches SA6 and SA5 must be continuously in the upper position.
3. The parameterization of thyristor converter for working in the
PROFIBUS-DP network
3.1. Brief information about the PROFIBUS-DP
PROFIBUS (PROcess FIeld BUS) is an open international standard of field
buses with wide range of application area in the automation of technological process.
Independence for different manufactures and openness of standard is guaranteed by
means of international EN 20170 and IEC 61158 norms.
The PROFIBUS-DP (Distributed Peripherals) is a one of communication
profiles of this standard. It is optimal solution for fast and low-cost data transmission
on the field level.
PROFIBUS-DP predominantly utilizes the master-slave method and data is
exchanged cyclically with the drives in most cases. PROFIBUS is a multi-master
system and allow to work simultaneously of few automation systems, human-
machine interface systems and decentralized execution units on the one bus.
29
The shielded twisted pair is widely used on practice (fig. 11) and it is allow to
transmit data with rates from 9,6 Kbit/sec (12 km) to 12 Mbit/sec (100 m). The
transition rate depends from the distance between the two units on the bus.
Fig. 11. Standard PROFIBUS-DP cable:
1 – conductor А; 2 – conductor В; 3 – shield; 4 – insolation
The PROFIBUS cables have a many different implementations for specific
applications. For example, there are a PROFIBUS cables for different movable units,
for underground setup also there are optical cable for high data transmission rates etc.
For PROFIBUS the RS485 data transmission method is used, which is based
on the half-duplex, asynchronous synchronization.
As a rule, the 9- pin connector is used on practice to connect the different units
each other. This connector is shown on the figure 12.
Fig. 12. Connector Sub-D
On the Sub-D connector there is a Switch, which closes the unusable parts of
the bus on the resistance. On the both ends on the bus this Switch mast be set in On
position.
For fail-safe operation in the network and to eliminate the hardware conflicts,
it is necessary that each of all devices in the bus will have the bus access at the
30
appointed time. Logic bus topology in the PROFIBUS can be built on master/slave
principles:
master – slave;
master – master (ring topology with marker);
combination of these two principles (hybrid method).
The “master – slave” communication is a centralized one. That is, the only one
master controls the access to the network and interrogates the slave devices on the
bus. In this variant, the slave units cannot to transfer the data without master request
and cannot by oneself to obtain admittance to the bus with some exceptions.
The “master – master” communication is a decentralized one. In this variant,
there are a few master units, which are connected to the bus by means of token ring.
And then, each master interrogates the specified slave units in the network.
Figure 13 shows the combination of these two methods for bus access. On the
figure 3 there are three master and five slave units. The master devices are serially
connected to the bus by means of token ring and receive the data from slave units.
Fig. 13. Hybrid method for bus access
All devices in on the PROFIBUS have its own addresses in the range from 0 to
127, which allow definitely to identify the devices. The addresses are set intentionally
and are independent from the physical location on the bus.
The Master units are divided in the two classes:
31
Master (class 1) – it is devices in the bus, which are usually exchanged
data cyclically.
Master (class 2) – programmers, diagnostic devices, human-machine
interface (HMI) units, etc. As a rule, they use acyclic data exchange. In
some cases, they can use the cyclic data exchange.
Examples of Masters (class 1) are the logical controllers Simatic S7-300, S7-
400 with embedded PROFIBUS interface, or communication processors, for example
CP 342-5. The Masters (class 2) units are HMI panels, programs for network setting
(for example STEP 7) and convertor parameterization (for example STARTER, Drive
Monitor).
As slave units the following devices can be used:
logical controllers Simatic S7-200 and controllers S7-300 in the slave
mode;
communication processors, for example CP 342-5, CP 248-2;
decentralized periphery ET-200;
semodrive sensors;
numerical program control systems – Sinumeric;
frequency convertors Sinamics, Micromaster etc.;
the communication board CBP2 for Simoreg DC Master Converters.
3.2. The Simoreg DC Master convertor as a slave unit on the PROFIBUS
The Simoreg DC Master acts only as a slave unit in the PROFIBUS network.
To connect the Simoreg to the bus the external communication board CBP2 is used.
The CBP2 communication board is mounted in the body of thyristor convertor. The
optional board features three LEDs (green, yellow, red) for displaying the current
operational status in the bus. The board is supplied with power via the basic unit. The
optional CBP2 board features a 9-pin Sub D connector (see fig. 12) for connection to
the PROFIBUS-DP system.
32
The bus system allows data to be exchanged very rapidly between the drives
and higher-level systems (for example Simatic). The drives are accessed in the bus
system according to the master/slave principle. The drives are always slaves. Each
slave is uniquely identified by a slave address, which can be set by means of
parameter.
Data are exchanged in message frames. Each message frame contains useful
data which are divided into two groups:
1. Parameters (parameter identifier value, PKW).
2. Process data (PZD).
The PKW area contains all transfer data which are needed to read or write
parameter values or read parameter properties.
The PZD area contains all the information needed to control a variable-speed
drive. Control information (control words) and setpoints are passed to the slaves by
the PROFIBUS-DP master. Information about the status of slaves (status words) as
well as actual values are transferred in the opposite direction.
The length of the PKW and PZD components in the message frame are
determined by the master. Only the bus address and, if necessary, the message frame
are set on the slaves.
The simplified structure of PKW and PZD areas is shown on the fig 14.
Fig. 14. Structure of data transmission telegram
Let’s consider the communication between the Simoreg DC Master Converter
and PLC. The communication between the thyristor converter and PLC is realized by
means of PROFIdrive profile in the electric drive. The drive profile selection is made
in the STEP 7 program during the hardware configuration.
33
The PROFIdrive profile (PRO), which is used in the Simoreg converter is
shown on the figure 15.
Fig. 15. Telegram types in the Simoreg DC Master Converter
In the second version of PROFIdrive protocol there are a five telegram types
(PRO), which are depicted on the figure. 15.
As can be seen from the figure, the most simple is a PRO3 profile, which is
able to start, stop and reverse electric drive and regulate the motor speed by means of
“Control word 1” (STW1) and “Speed setpoint signal (Main setpoint)” (HSW).
Control word 1 and the Speed setpoint signals are the 16-bit signals, which are
receiver from master unit. In response to master request, the Simoreg DC Master
sends the Status word (ZSW1) and actual speed signal (HIM). This signal can be used
in the PLC to control the electric drive operation.
There are no the parameter changing mechanism in the PRO3 telegram. If there
is a need to change converter parameters via PROFIBUS, it is necessary to select
PRO1 or PRO2 profile. In the PRO2 profile also it is possible to send and receive
different variables from or to PLC. The variable choosing is made by means of some
parameters, which will describe below. For example, it is possible to send to the PLC
the faults codes, actual armature current or motor electromagnetic torque etc. Also it
34
is possible to receive from PLC the “Control word 2” (STW2) and use this word for
controlling of electric drive.
The PRO5 telegram allow to fully free adjusting of sanded and received data
between the Simoreg converter and PL, but one should add that without “Control
word 1” and “Speed setpoint signals”.
3.3 Control and Status words and speed setpoint signal
The PRO3 profile in the Simoreg converter is the most simple for controlling the
electric drive via PROFIBUS-DP.
“Control word 1” is a 16-bit signal, where each bit has some specific function,
such as: start, stop or reverse of electric drive.
Let’s consider how we can to control of electric drive via “Control word 1”,
which is shown in the table 4.
Table 4
“Control word 1” for Simoreg DC Master Converter
Bit Value Function Description
1 2 3 4
0 1
0
ON.
OFF 1
Turn electric drive into the ready to run state.
Off 1 – stopping by means of ramp-function generator.
1
1
0
Operating
condition
OFF2
–
Off 2 – Instantaneous pulse disable, drive coasts to a
standstill.
2
1
0
Operating
condition
OFF3
–
Off 3 – Rapid stop: Shutdown with the fastest possible
acceleration rate.
3
1
0
Enable
operation
Disable
operation
Closed-loop control and pulses are enabled.
Closed-loop control and pulses are disabled.
4
1
0
Operating
condition
Disable RFG
–
Output of RFG is set to 0 (the fastest possible braking
operation), converter remains in the ON state.
35
Table 4. Continuation
1 2 3 4
5 1
0
Enable RFG
Stop RFG
Ramp-function generator start.
Setpoint currently supplied by the RFG is “frozen”.
6 1
0
Enable setpoint
Disable setpoint
Value selected at the RFG input is activated.
Value selected at the RFG input is set to 0.
7
1
0
Fault
acknowledge
–
Fault is acknowledged by a positive edge, Simoreg then
switches to “starting lockout” state.
8 1
0
CW inching
–
Clockwise rotation of electric drive.
9 1
0
CCW inching
–
Counterclockwise rotation of electric drive.
10
1
0
Control by PLC
No control by
PLC
Master transfers valid setpoint.
There is no setpoint from master.
11
1
0
Enable positive
direction of
rotation
Positive
direction of
rotation disable
The positive direction of rotation is allowed.
The positive direction of rotation is not allowed.
12
1
0
Enable negative
direction of
rotation
Negative
direction of
rotation disable
The negative direction of rotation is allowed.
The negative direction of rotation is not allowed.
13 1
0
MOP UP
–
Motor potentiometer UP.
–
14 1
0
MOP DOWN
–
Motor potentiometer DOWN.
–
15 1
0
External fault
No external fault
Fault signal from PLC (F021).
No fault signal.
Let’s consider some examples of “Control word 1” for the most common
command, which is shown in the table 5.
To simplify the “Control word 1” recording format it is useful to use the
hexadecimal format (Hex).
36
Table 5
Examples of “Control word 1”
Command
Control word in the binary
format (bit numbers)
12 8 4 0
Control word
in the hexadecimal format
Ready to run (Stop) 0001 1100 0111 1110 1C7E
Start forward 0001 1100 0111 1111 1C7F
Start backward (reverse) 0001 0100 0111 1111 147F
Fault reset 0001 1100 1111 1110 1CFE
Before the starting of electric drive, it is necessary to prepare the Simoreg
convertor to operation. For this you need to send the 1C7E (hex) value from the PLC
to the “Control word 1” area into converter. Then, the starting command 1C7F should
be sent in the “Control word 1” area. If the speed setpoint is not equal to zero, the
electric drive will starts rotation.
The “Speed setpoint signal (Main setpoint)” also consists of 16 bits as and
“Control word”. The 100 % of speed setpoint corresponds to the 4000 (hex) value by
default. This value is a 214
, that is the rated motor speed (100 %) uses the 14 bits of
the word. So, the maximum speed setpoint value is a 200 % taking into account that
the high bit of word is used for speed setpoint sign.
To convert of speed setpoint from percent to the hex value it is useful to use
the intermediate values in the decimal format. The some examples of speed setpoint
values in the percent, hex and decimal formats are shown in the table 6.
Table 6
Speed setpoint examples
Speed setpoint value, % Speed setpoint value, (dec) Speed setpoint value, (hex)
100 16384 4000
50 8192 2000
20 3276 CCC
10 1638 666
The using of “Control word 1” and “Speed setpoint” signal are enough to
control the DC electric drive via PROFIBUS.
37
But for reliable operation of electric drive it is necessary to receive from
convertor the signals: “Ready to run”, “Faults”, “Alarms”, “Operation mode” etc.
This is done by means of “Status word”, which is shown in detail in the table 7.
Table 7
“Status word 1” of Simoreg DC Master Converter
Bit Value Function Description
1 2 3 4
0
1
0
Ready for
switch ON
Not ready for
switch ON
Power supply switched on, electronics initialized, pulses
disabled.
1
1
0
Ready to run
Not ready to run
Converter is switched on (ON command is applied), no
fault is active, inverter can start when “Enable
operation” command is issued.
Causes: No ON command, fault, OFF2 or OFF3
command, starting lockout.
2
1
0
Operation
enabled
Operation
disabled
Drive is ruining (See control word, bit 3).
Pulses disabled.
3
1
0
Fault is active
–
Fault, see fault parameter r0947. Drive is faulty and thus
inoperative. It switches to starting lockout state after
successful correction and acknowledgement of fault.
4
1
0
–
OFF2 command
applied
–
See control word, bit 1 (table 4).
5
1
0
–
OFF3 command
applied
–
See control word, bit 2 (table 4).
6
1
0
Switch on
inhibit
No switch on
inhibit
Drive can be restarted only by OFF1 followed by ON.
7 1
0
Alarm is active
–
Alarm, see alarm parameter r2110. Drive still in
operation.
8
1
0
No setpoint
/act.val.
deviation
Setpoint/act.val.
deviation
Setpoint/actual value deviation within tolerance range.
9
1
0
PZD control
-
PZD control requested (always 1)
38
Table 7. Continuation
1 2 3 4
10
1
0
Max. speed
reached
Max. speed not
reached
Motor actual speed is higher or equal to the maximum
speed P373
11 1
0
Undervoltage
No undervoltage
Undervoltage fault (F006) is active.
No undervoltage fault is active
12
1
0
Main contactor
request
No contactor
request
Request to energize main contactor.
No request to energize main contactor.
13 1
0
RFG active
RFG not active
Ramp-function generator is active.
Ramp-function generator is not active.
14
1
0
Positive speed
setpoint
Negative speed
setpoint
Clockwise rotation of electric drive.
Counterclockwise rotation of electric drive.
15 1
0
Spare Not used
The “Actual speed” signal uses the same format as a “Speed setpoint” and also
can be sanded to the PLC via the PROFIBUS.
Some examples of “Status word 1” in the Simoreg DC Master converter are
shown in the table 8.
Table 8
“Status word 1” examples
State
Status word in the decimal
format (bit numbers)
12 8 4 0
Status word in the
hexadecimal format (hex)
Ready to run (Stop) 0100 0010 0011 0001 4231
Run forward 0110 0011 0011 0100 6334
Run backward 0010 0011 0011 0100 2334
Fault signal 0100 0010 0011 1000 4238
One should add, that to control the frequency convertors such as Micromaster
and Sinamics via PROFIBUS-DP same principles are used.
39
3.4. The using of PKW mechanism for processing parameters
The PKW mechanism is used to read and write parameters of Simoreg
converter via the PROFIBUS network. This mechanism can use both acyclic and
cyclic data transfer. To access the reading or writing of converter parameters it is
necessary to select the profile PRO1 or PRO2 (see figure 15) during the hardware
configuration in the STEP 7 program [2].
The parameter area for PKW mechanism always consists of 4 words. Structure
of this area is shown on the figure 16.
Fig. 16. Parameter area of PKW mechanism
Let’s consider the all three part of parameters area separately. First word
consists of 16 bits and is used for parameter identifier (PKE). The parameter
identifier (PKE) contains the number of the relevant parameter and an identifier
which determines the action to be taken. Structure of parameter identifier is depicted
on the figure 17.
Рис. 17. The word structure of parameter identifier area
The parameter identifier (PKE) consists of following areas:
Bits from 0 to 10 are used for parameter number (PNU – parameter
number). The maximum parameter number is 2048 (211
), therefore to access
to parameter numbers more than 2000 the additional offset displacement in
the index area (IND) is set;
40
Bit 11 (SPM) is reserved and its value always equal to zero;
Bits 12 to 15 (AK) contain the request or the response identifier.
The meaning of the request identifier for request telegrams (master →
converter) is shown in table 9.
Table 9
Request identifier (master → converter)
Request
identifier Functions
Response
identifier
positive negative
0
1
2
3
4
6
7
8
9
No request
Request parameter value
Modify parameter value (word)
Modify parameter value (double word)
Request descriptive element 1
Request parameter value (array)
Modify parameter value (array, word)
Modify parameter value (array, double word)
Request number of array elements
0
1 or 2
1
2
3
4 or 5
5
5
6
7 or 8
7 or 8
7 or 8
7 or 8
7 or 8
7 or 8
7 or 8
7 or 8
7 or 8
For example, to change parameter P303 [Ramp-up time] we should set the
parameter number (100101111 – 303) in the PNU area and send request (10 – 2) to
the AK area. If the parameter changing passed without any errors that the in response
we will have the number – 2 response identifier. If there is some error during the
parameter changing, in response we will have the numbers – 7 or 8 response
identifiers. The meaning of response identifiers is shown in the table 10.
Table 10
Response identifier (inverter → master)
Response
identifier Functions
0
1
2
3
4
5
6
No response
Transfer parameter value (word)
Transfer parameter value (double word)
Transfer descriptive element 1
Transfer parameter value (array word) 2
Transfer parameter value (array double word) 2
Transfer number of array elements
Positive responses
7
8
Cannot process request (with error number)
No master control status for PKW interface Negative responses
41
If the response identifier is 7 (cannot process request), then one of the fault
numbers will be stored in parameter value 2 (PWE2) [2].
The second word in the parameter area (PKW) is a parameter index. The
structure of this word depends of data transferring types (cyclic or acyclic). On the
figure 18 the structure of parameter index for these two data transfer types is shown.
a) Cyclic data transferb) Acyclic data transfer
Fig. 18. Structure of parameter index (IND)
As can be seen from the figure 18, that main different is that the subindex and
parameter page selection is interchanged. Let’s consider the cyclic data transfer
between the PLC and Simoreg converter.
The convertor has index parameters. The index can be switched by means of
bits 16 and 17 of “Control word 2” [5]. The master can request to the different
parameter index (subindex) by means of PROFIBUS network. Parameter subindex
occupies a high 8 bits of IND and can take values from 0 to 255 (28).
The page parameter selection is used for the accessing to the parameters, which
number are higher than 2000. In the Simoreg DC Master there are no parameters
numbers higher than 2000, so the page parameter selection mechanism is not
considered here.
42
The parameter value is set in the PWE area, which consists of two words. The
32-bit value is transferred through the high word PWE1 and the lower word PWE2.
As to the 16-bit values, they are transferred by means of PWE2 word, the PWE1
word is not used in this case. The parameter values area is shown on the figure 19.
Fig. 19. Parameter values area
During the work with convertor parameters via PROFIBUS it is necessary to
observe the following conditions:
A request or a response can only ever refer to one parameter.
The master must repeat a request continuously until it has received the
appropriate response.
The complete request must be sent in one telegram. Request telegrams
cannot be split. The same rule applies to responses.
In the case of response telegrams which contain parameter values, the
drive always returns the momentary parameter value when repeating
response telegrams.
If no information needs to be fetched from the PKW interface in cyclical
operation (only PZD data are relevant), then the "No request" request
telegram must be issued.
Let consider some examples of parameter requesting, which are shown in the
table 11.
43
Table 11
The examples of using PKW mechanism
Description PKW (hex format)
Comments PKE IND PWE
Reading
Р0303
Request 112F 0000 0000 0000 Р0303 – rump-up time (10 sec –
4120 16-bit IEEE float point). Response 112F 0000 0000 4120
Reading
Р0304
Request 1130 0000 0000 0000 Р0304 – rump-down time (10 sec –
4120 16-bit IEEE float point). Response 1130 0000 0000 4120
Writing
Р0303
Request 212F 0000 0000 4000 Р0303 – rump-up time (2 sec – 4000
16-bit IEEE float point). Response 212F 0000 0000 4000
Evaluating an
error response
Request 212F 0000 0000 4000 Fault – drive is in operation mode.
Parameter changing is not allowed. Response 712F 0000 0000 0011
One should add, that the program in STEP7 for parameter changing is not
describer here. For more detail information see [2].
3.5. The parameterization of Simoreg convertor for working from
PROFIBUS-DP
Let’s consider the most important communication parameters of Simoreg DC
master converter:
1. Parameter U712 [PRO type] defines of the number of words in the
parameter and process data section of the telegram (required only if the PPO type
cannot be set via PROFIBUSDP master). So it is not necessary to set this value.
2. Parameter U722 [Telegram failure time for process data (0 = deactivated)].
If this monitoring function is activated, the DP master passes a time value (watchdog
time) to the slave when the link is set up. If no data are exchanged within this period,
the slave terminates the process data exchange with the SIMOREG converter. The
latter can monitor the process data as a function of U722 and activate fault message
F082.
3. P918 [Bus address]. It is necessary to set this value from 0 to 127 according
to the STEP7 hardware configuration.
4. P927 [Parameterization enable]. Parameter should be set if parameters are to
be assigned via PROFIBUS with using PKW mechanism.
44
The data exchange between the Simoreg DC Master and communication board
CBP2 is shown on the figure 20.
As can be seen from the figure, the “control word 1” and “speed setpoint”
receive from the board to the connectors K3001 and K3002. The connector K3001
(Control word 1) can be divided into the individual bits, which are used to send
commands – start, stop, fault acknowledge and reverse to electric drive.
By means of parameter U734 the variables, which should be sent from the
electric drive to PLC is selected. By default the “Status word 1” and “Actual speed”
is sent.
Fig. 20. Data exchange between Simoreg and technological board CBP2
So, to control electric drive from PROFIBUS it is necessary to set the
following parameters:
5. Set parameter P433=K3002 [Source for standard setpoint]. This parameter
applies the “Speed setpoint” signal to the thyristor converter.
45
6. Set parameter P648=K3001 [Source for control word 1]. This setting allow
to setup commands (start, stop, fault acknowledge and reverse etc.) from the
PROFIBUS network (see tables 4, 5).
One should add, during the work from PROFIBUS-DP, the switches SA6 and
SA5 must be continuously in the upper position.
3. THE PLOTTING OF TRANSIENTS OSCILLOGRAMS WITH USING THE
DRIVE MONITOR SOFTWARE
For Simoreg DC Master Convertor in the Drive Monitor Software there is a
function of transients building. To turn program in the transient building mode, it is
necessary to press the button or - Trace in the program window. After that,
the Drive Monitor windows will looks like in the figure 21.
Fig. 21. Drive Monitor window in the transients building mode
46
The buttons assignment of the Drive Monitor in the transients building mode
(see fig .21):
– Y – axis: gain up – increases the scale of the 0Y axis for selected
variable.
– Y – axis: gain down – decreases the scale of the 0Y axis for selected
variable.
– Y – axis: automatic scaling – sets the automatic scale of the 0Y axis for
selected variable.
– Min- And Max- marker On/Off – shows the markers for maximum and
minimum values for selected variable.
– General Settings… – shows the setting window of main setting for
external view of transients building.
– Open trace file – opens the file with saved transients.
– Save trace file – saves the transients oscillogram in the files with the
following extensions: *.trс, *.txt, *.wmt.
– Show Record info – shows the information about the oscillogram
recording settings.
– Copy traces to clipboard – copies the oscillogram to the clipboard in
the graphic format with white background. The information about markers is not
saved.
– Show ASCII list of waveform data – shows the oscillogram points in
the text format.
– Print all visable traces – prints the visable transients graphics.
– Help; about trace – shows information about the transients recording in
the Drive Monitor program.
– In the field dt the time
difference between the two cursors is displaed, in the fied dv the amplitude difference
beetwin the two cursors for selected variable is displaed. And the field @ show the
47
current time position for selected cursor with respect to trigger time and amplitude of
slected varible.
– Immidiate starts of transients recording.
– Starts transients recording acording to the trigger settings.
– Read recorded data fron convertot to PC.
– Shows the windows with main settings of transients
recording (see fig. 22).
Fig. 22. The windows of transients recording settings
In the lift part of setting windows (fig. 22) the displayed variables is selected.
The most important connectors for different variables are shown in the table 12.
48
Table 12
The connector for displaying different variables
Connector number Connector description
К0117 Motor armature current
К0142 Motor electromagnetic torque
К0167 Speed actual value
К0170 Speed setpoint value
К0287 Motor EMF value
К0290 Motor magnetic flux
One should add, that the all connector from functional diagram mentioned
below (fig. 7-10) can be displayed on the trace by selecting the appropriate
connectors in the trace setting window.
In the right part of setting window in the fields of recording settings the
recording interval and pretrigger values are set.
Recording interval sets the time for transients recording. Default value is
1 66,7/50=1,33 sec. After that time will be exceed, the transient recording will be
stopped.
Pretrigger sets the value on the 0X axis when the trigger condition is
executed. To put in other words, it is a time in percent of Recording interval, which
is recorded before the trigger conditions occurred.
The using of trigger allows users to start recording of transients according with
different external condition. In the channel field the some variable is selected. This
value is compared to the value in the field Trigger value. And if value of this
variable will exceed (Trigger conditions - >) the trigger value the run of transients
recording will be started. The trigger mode of transients recording is switched-on by
means of Start button.
The Go button is used for immediate starts of transients recording and trigger
setting in this case is not work. To stop the transients recording, it is necessary to
press the Stop button.
The using of Start button is more preferable on practice because off in this case
the transients recording are realized automatically by means of some external
49
conditions. The binectors values can be also displayed on the trace window by means
of BiCo conversion button. It is also possible to start transients recording when the
fault of thyristor convertor is occurred. The selected variable and recording settings
can be saved in special file be means of save file button. To load this file the load file
button is used.
Attention! During the transients recording it is necessary to watch that the
scales of all variables in the trace window are the same. In this case there are no
problems with different scales for different variables.
In conclusion, one should add, that the Trace function in the Drive Monitor
Software is a powerful instrument for recording the different transients in the DC
electric drives.
50
GLOSSARY
1. Automatic Control System (Автоматическая система управления) – is
the system that can control a plant (such as a direct current motor or some
technological process) by using the different controllers without human.
Automation control systems allow to reduce the need for human work in the
technological complexes.
2. Block Diagram (Functional diagram) (Функциональная схема) – is a
schematic representation of control system, on which the transition or transfer
functions are represented by blocks connected by lines, which show the
relationships of the different blocks.
3. Closed Loop Control System (Замкнутая система автоматического
управления) – a closed system with feedback or feedforward.
4. Closed Loop Transfer Function (Передаточная функция замкнутого
контура) – is a mathematical expression of transfer function describing the
closed loop control system.
5. Current Controller (Регулятор тока) – is a device or program algorithm to
control the motor armature current in closed loop control system with current
negative feedback.
6. Digital Control System (Цифровая система управления) – is a control
system implemented on special microcontroller which acts as system
controllers. Digital controller is a discrete unit thus the Laplace transform is
replaced with the Z-transform. Digital microcontroller also needs some
additional device such as analog-to-digital and digital-to-analog convertors.
7. Direct Current Motor (Двигатель постоянного тока) – is an electrical
machine designed to be run from a direct current power source.
8. Disturbance action (Возмущающее воздействие) – is a temporary change
in average environmental conditions that causes a pronounced change in the
51
control system output. Outside disturbance for control system often is a load
torque on the electric motor shaft.
9. Electric Drive (Электропривод) – is electro mechanical system that converts
electrical to mechanical energy.
10. Electromagnetic Torque (Электромагнитный момент) – also called
electromagnetic moment or moment of force, is the tendency of a force to
rotate an electric motor rotor about a shaft axis.
11. Feedback (Обратная связь) – the output signal of the plant sensor (speed,
current, position) is closed into control system as an input usually with
negative sign.
12. Filter (Фильтр) – hardware or software device in control system intends to
reject different perturbation like noise and oscillations.
13. Frequency Response (Частотная характеристика) – the control system or
plant response to sinusoidal signals of different frequencies. Frequency
response is the measure of any system's output spectrum in response to an
input signal.
14. Integrator (I-controller) (Интегратор, И-регулятор) – hardware or
software device in control system that has the effect of integrating the input
signal.
15. Magnetic Flux (Магнитный поток) – is a measure of the amount of
magnetic field passing through a given surface.
16. Modular Optimum (Модульный оптимум) – optimal method for controller
adjustment which provides a non-oscillatory closed-loop response with small
overshoot for different closed loops.
17. MATLAB – commercial software having a Simulink toolbox which used for
simulation study of plant and control systems.
18. Microprocessor control system (Микропроцессорная система
управления) – The automatic control system which is implemented on the
microprocessor.
52
19. Negative Feedback (Отрицательная обратная связь) – a feedback system
where the plant output signal is subtracted from the input signal and the
difference is input to the control system.
20. Open Loop Control System (Разомкнутая система управления) – when
the system is not closed, its behavior has a control error under different
disturbance in spite of using controllers.
21. Optimal Control (Оптимальное управление) – a branch of control
engineering that deals with the minimization of different criterions, or
maximization of system performance.
22. Order (Порядок) – the order of a polynomial is the highest exponent degree
of the variable in the characteristic equation. The order of a control system is
the order of the denominator polynomial of transfer function.
23. Oscillations (Колебания) – is the variation of different physical variables,
typically in time, about a mean value. Oscillations often occur in control
systems during sensors scanning (for example: current or speed sensors).
24. Overshoot (Перерегулирование) – is when an output signal of loop or
control system exceeds its steady-state value of several per cent. It appears
especially in the step response of bandlimited control systems.
25. Proportional-integral-derivative Controller (PID controller) (ПИД-
регулятор) – is a fundamental control loop feedback controller widely used in
industrial control systems. The PID controller is the most commonly used
algorithm in electric drive control system. A PID controller calculates an error
as the difference between a measured process variable and a desired setpoint.
The controller tends to minimize the error by adjusting the controller output
variable. The P- and PI-controller are the special cases of PID-controller.
26. PROFIBUS (PROcess FIeld BUS) is an open international standard of field
buses with wide range of application area in the automation of technological
process.
53
27. Positive Feedback (Положительная обратная связь) – a feedback system
where the plant output signal is added to the system input, and the sum is input
into the control system.
28. Ramp-function generator (Задатчик интенсивности) – is the nonlinear
device that is mounted in the setpoint cannel of controlled variables and its aim
is to limit the rate of setpoint signal in input of automatic control system.
29. Symmetric Optimum (Симметричный оптимум) – optimal method for
controller adjustment, which provides a symmetric logarithmical frequency
response with respect to cutoff frequency. Closed loop control response in such
systems has overshoot value about 50 percent.
30. Speed Controller (Регулятор скорости) – is a device or program algorithm
to control the motor angular speed in closed loop control system with speed
negative feedback.
31. Stability (Устойчивость) – is a feature of control system to return to initial
condition after applying of different disturbances.
32. Step Response (Реакция на ступенчатое воздействие) – describes the
reaction of a system as a function of time in response to unit-step input signal.
33. Steady State Error (Установившаяся ошибка) – at steady state, the
amount by which the system output value differs from the reference value
(examples: speed error, armature current error).
34. Subsequent coordinate control (Подчиненное регулирование
координат) – is fundamental prince of automatic control theory and is widely
used in automatic control system of electric drives. According to this principle
the control systems are engineered in view of multiloop control systems in
which each inner loop is subordinated to output loop.
35. Thyristor Power Converter (Силовой тиристорный преобразователь) –
is used in direct current electric drives to create a DC variable voltage from AC
power supply.
54
36. Transfer Function (Передаточная функция) – the ratio of the system
output to its input, in the P-domain. The Laplace Transform of the function's
impulse response.
37. Transient (Переходный процесс) – is the response of a system to a change
from equilibrium.
38. Unity Feedback (Единичная обратная связь) – a feedback system where
the feedback loop element has a transfer function equal to 1.
55
REFERENCES
1. Шрейнер Р. Т. Системы подчиненного регулирования
электроприводов [Текст]: учеб. пособие / Р. Т. Шрейнер. Екатеринбург: Изд-во
ГОУ ВПО «Рос. гос. проф.-пед. ун-т», 2008. 279 с.
2. Системы управления электроприводами переменного тока.
Управление электроприводами по сети PROFIBUS [Текст]: учебно-
методическое пособие / Ю. В. Плотников, В. Н. Поляков. Екатеринбург: УрФУ,
2011. 106 с.
3. Терехов В. М. Системы управления электроприводов [Текст]:
учебник для студ. высш. учеб. заведений/ В.М. Терехов, О.И. Осипов; под ред.
В.М. Терехова. - 2-е изд., стер. - М.: Издательский центр Академия, 2006. 304 с.
4. ELECTRIC DRIVE CONTROL SYSTEM (SIMOREG DC
MASTER) [Text]: Methodological course book for laboratory work of «Electric
Drive Control System» discipline. / author Y.V. Plotnikov. Ekaterinburg: Ural
Federal University, 2011. 19 p.
5. SIMOREG DC-MASTER. Operating Instructions for Microprocessor-
Based Converters from 6kW to 2500kW for Variable-Speed DC Drives [Text].
Siemens. 2007. 736 p.
6. SIMOREG DC Master 6RA70. Series Tips on Configuration,
Hardware, Software, and Closed-Loop Control [Text]. Converters with
microprocessor from 6kW to 1900kW for variable-speed DC drives. Siemens. 2002.
20 p.
56
Electronic textbook
Plotnikov Yuriy Valerievich
ELECTRIC DRIVE CONTROL SYSTEMS
(Parameterization of Thyristor Converters – SIMOREG DC
MASTER)
Preparing for publication N.V. Lutova
Computer make-up Y. V. Plotnikov
Recommended by Methodic union
Allow to publication
Date of publication – 05.04.2013
Electronic format – pdf
Size 2,95 p.
620002, Yekaterinburg, Mira street, 19
Data portal YrFU
http://www.ustu.ru