allen bradley df1 setup summary - software...

TOP Server 5.19

Configuration Guide:

Allen Bradley DF1 Device

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Table of Contents

Introduction 3

Channel Setup 3

Device Setup 11

Further Information 19

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Introduction

This document is intended to provide an easy to use reference guide on configuring a connection to an

Allen Bradley DF1 device using the TOP Server. It is not intended to be comprehensive, and the help file

should be referenced for any additional information – if needed. This document will describe the channel

and device setup, give a summary of the settings that will be encountered – and when it is appropriate to

change them from the default values.

Channel Setup

1. The first step in configuring a connection to a DF1 device from TOP Server is to create a Channel.

A channel represents a communication medium from the PC running TOP server to the device. In

the case of DF1, the Channel will represent the serial port over which communications will occur.

2. The Channel name is user configurable, and will be how the Channel appears in the TOP Server

tree view – i.e. how clients will reference devices configured under this channel:

3. Click next and choose the Allen Bradley DF1 driver from the Driver dropdown list. This selection

determines which protocol will be used to communicate over the channel. The “Enable Diagnostics”

checkbox has not impact on communications so can be left unchecked, but statistic tags will be

inactive until diagnostics are enabled.

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4. Click next and choose whether or not this channel should be included in a Virtual Network, and if

‘yes’ which Virtual network the channel should be assigned to.

a. The Transactions per cycle specifies the number of single read/write transactions that can

occur on the channel. When a channel is given the opportunity to communicate, this

number of transactions is attempted.

b. The Network Mode is used to control how channel communication is delegated:

i. Load Balanced mode – Each channel is given the opportunity to communicate in

turn, one at a time.

ii. Priority mode – Channels are given the opportunity to communicate according to

transaction priority:

1. Channels with pending writes have the highest priority

2. Channels with pending explicit reads (through internal plug-ins or external

client interfaces) are prioritized based on the read’s priority.

3. Scanned reads and other periodic events (driver specific).

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5. Click next and choose the appropriate connection medium and settings for devices under this

channel. For a serial port the COM settings must match those of the devices on the bus, for a

Modem the appropriate dialing and connection properties should be set, and for Ethernet

Encapsulated communications the Network Interface Card on the local computer should be

selected.

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6. Click next to configure the connection behavior.

a. Report communication errors will log any errors specific to the port we are attempting to

communicate with to the TOP Server event log. On serial lines where interference is

expected, unchecking this option can prevent the TOP Server event log from flooding with

connection related events – this should be done with care, as this will also prevent

legitimate connection errors from being logged.

b. Close connection when idle will terminate the connection when it is not in use for the

specified number of seconds.

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7. Click next to review the Write optimization settings for this Channel. These will generally be left at

the default value, but can be altered as needed.

a. Write all values for all tags will queue all write requests and issue them in the order they

were received.

b. Write only latest value for non-Boolean tags will not queue all writes, but only write the

last value that was received from the client application for any non-Boolean tags.

c. Write only latest value for all tags will not queue any writes, and simply write the last

value that was received from the client application for any points.

d. The Duty Cycle determines how many writes will be processed per 1 read request. Since

writes are treated with higher priority this can be used to improve communication rates in

write-heavy channels

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8. Click next to review how the driver will handle non-normalized floating point values. This can

generally be left at the default value, unless non-normalized values are expected (e.g. Non-A-

Number or infinity)

9. Click next to specify the Link Settings. The Station Number specifies the ID of the local machine

running TOP server, and should be set based on the device being communicated with (excluding

radio modems):

a. If the destination device is on a DH+ or DH-485 network, communication must go through a

Serial-to-DH+/DH-485 converter (i.e. KF2/KF3 module). In this case, the device being

communicated with is the converter, not the destination device itself (which is a Micrologix,

Micro800, SLC500, or PLC-5). The station number for this configuration should be set to

the converter's node address as the converter will be the acting master on the serial bus.

b. If the destination device is not on a DH+ or DH-485 network, the device being

communicated with is a Micrologix, Micro800, SLC500, or PLC-5 PLC. The station number

for this configuration can be set to an arbitrary unique address.

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The appropriate link protocol should also be selected:

c. Full-duplex protocol is used over a point-to-point link, allowing for high performance two-

way communications between peers.

d. When checked, the “Only accept response for Station Num” parameter limits the

acceptance of responses to those that are destined for the station as indicated by the

Station Num field.

e. Half-Duplex Protocol is a multi-drop protocol with one master and one or more slaves.

Generally, Half-Duplex provides lower data throughput than Full Duplex, but it adds the

flexibility of being able to communicate with multiple devices from a single COM port. In

Half-Duplex Master mode the driver is the master and all devices on the network are

slaves, and should be appropriately configured as Half-Duplex Slaves, since a network is

limited to a single master node.

f. If the destination device is on a DH-485 or DH+ network, communication must go through a

KF2/KF3 module respectively. If the KF2/KF3 module is configured as a Half-Duplex Slave,

the KF2/KF3 Half-Duplex Master Link Protocol must be chosen.

g. The Radio Modem protocol is a command/reply protocol. There are no ACKs or NAKs

during the request/response procedure. This reduces the number of bytes the radio

modems have to transmit and receive to complete a transaction. This protocol supports full-

duplex communications over a point-to-point link allowing for high performance two-way

communications between peers. It also supports master/slave communications allowing for

multi-drop configurations. Performance exceeds both Full-Duplex and Half-Duplex

Protocols.

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10. The last dialog will summarize the selected Channel settings. If all settings are correct, selecting

Finish will finalize the configuration and create the Channel.

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Device Setup

1. Click to add a device to the newly configured Channel

2. The Device name is user configurable, and will determine how the device appears in the TOP

Server Tree view, and how client applications access the device.

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3. Select the appropriate Device model. Supported devices are MicroLogix, SLC500 series controllers,

and PLC5s.

4. Specify the Device’s device ID on the network, and whether the specified address is in Octal or

Decimal.

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5. Specify the devices Scan Mode settings for Subscription based clients. In systems where

bandwidth utilization is not a concern, this setting should be left at the default. Other options

include:

a. Respect client specified scan rate – Will respect the requested scan rate from client

applications to determine how often to scan the device

b. Request data no faster than… - Will set a ceiling; data will be requested no faster than

the specified time value.

c. Request all data at… - All data will be requested at the specified timing interval

d. Do not scan, demand poll only – there will be no automatic scanning done of the device,

unless a plug-in or client application manually triggers the poll (via the _DemandPoll

system tag)

e. Respect tag specified scan rate – respects the scan rate specified at the tag level

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6. The timing settings should be set appropriately based on the type of connection, and the level of

congestion on the network. These can generally be left at the default, and increased as needed.

Due to the lag introduced in telemetry scenarios it is a good idea to increase these during initial

setup and then come back and fine tune them as appropriate.

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7. The Auto-Demotion settings will determine whether unresponsive devices will be taken out of the

polling cycle for a specified period of time. In situations where multiple devices are configured under

a single channel it is recommended to enable auto-demotion, and discard write requests on devices

that are written to frequently. Write requests will overwrite the auto-demotion period, and attempt a

connection immediately. Since devices under a channel are treated sequentially, this will prevent a

downed device from repeatedly slowing down communications for other devices on the channel.

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8. Specify whether the device is configured to expect CRC or BCC checksums – this must match the

device side settings or TOP Servers requests will not be answered. The Request size can be used

to set the size of the data request packets, and is vital in fine-tuning application performance,

particularly in telemetry systems.

a. Large Request Size – Should be used when large memory ranges of contiguous registers

are being requested.

b. Small Request Size – Should be used if data is spread in the PLC address space

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9. If you are communicating with a PLC-5, you will have the option to swap floats words. Generally is if

the device transfers the lower word first, the upper word in the packet on the serial link does not

require word swapping. This only applies to PLC-5 emulated devices; that is, devices that use the

Allen-Bradley DF1 protocol with PLC-5 commands. Allen-Bradley PLC-5 devices always transfer

the upper word first followed by the lower word so the Float words must be swapped. This is the

default setting. SLC and Micrologix users can select whether the driver will natively support Float

access to Integer Files. The default setting is Yes.

These settings should be left at the default, unless they are known to be different.

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10. Specify whether or not to block write supporting function files. Function files are structure-based

files, similar to PD and MG data files, and are unique to the Micrologix 1200 and 1500. Unless

known to be different, this setting should generally be left at the default.

11. After reviewing the device settings in the summary, clicking Finish will create the device.

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12. Tags can now be configured statically in the server, or dynamically from the client application. For

help with the proper addressing syntax the appropriate driver help file section should be referenced.

Further Information

This guide is intended to server as a quick, step-by-step, guide on configuring an Allen Bradley DF1 device

in the TOP Server v5.x. It is not intended to be a comprehensive ‘how-to’ regarding the DF1 driver, and the

TOP Server help file should be referenced for further information.

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