|Table of Contents|
The RediGate Configuration Manual describes the configuration of many of the RediGate's standard features using the ACE program. This document gives additional instructions for configuring the RediGate to use the following protocols:
Allen Bradley DF1 & CSP Protocol Description
This document is not intended to provide a detailed description of the protocol(s) involved, nor to disclose proprietary information that may belong to other parties. Depending on the protocol, it may be necessary to refer to other vendor protocol documentation or device configuration details to understand how the RediGate should be configured to interface with it. This section provides a brief discussion of the protocol for the purpose of understanding the RediGate's configuration objects.
The Description and Enabled properties are included in ACE as part of each object but are not mentioned here. The "UFF External" property is only mentioned for the objects where it is typically used, but should normally be left unchecked.
DF1/CSP Master Channel
The structure of ACE objects for a Master Channel used for DF1 or CSP protocol is shown below:
- When using DF1 serial master, the Response Timeout is unused, because the AsyncCircuit object defines various timeouts for the DF1 protocol.
- In the Scan Table, only include the first Poll Record of a "Continuation Poll," not any subsequent poll records that are part of the same poll definition.
DF1 RS-232 Async Circuit
The DF1 RS-232 Async Circuit is a special serial communications path to one or more Allen Bradley DF1 field units from a common Master Channel. Use this circuit instead of the generic AsyncCircuit when configuring a DF1 serial field unit under a Master Channel. You should not use the standard AsyncCircuit when polling DF1 PLCs.
|DH Link Type|
Select the Allen Bradley link type (DH or DH+).
Configure this to "DH." The RediGate does not currently support the Data Highway Plus (DH+) protocol, which requires special hardware.
|Station DHP Address|
Enter the DF1 (master) station address taken by the RediGate on the Data Highway network.
Note that the master station address is different from the device address being polled, which is configured under the FieldUnit definition.
Select the link protocol to use ('Full Duplex' or 'Half Duplex').
This should be set to match the full-duplex (peer to peer) or half-duplex setting of the PLC.
Select the Async serial port to use for this circuit.
The selected port must be defined as an AsyncPort object under Networks, where its serial properties (baud rate, etc.) are defined.
Enter the message timeout in milliseconds. This is the amount of time to wait for a message response.
In the DF1 protocol, there may be multiple messages to a single poll, such as acknowledgments.
|Message Timeouts||Enter the number of message timeouts before declaring a message to have failed.|
Enter the poll timeout in milliseconds. This is the amount of time to wait for the initial byte of a response to a poll.
For DF1 used on an Async Circuit, the Master Channel's Response Timeout parameter is unused.
|Poll Timeouts||Enter the number of poll timeouts before aborting a poll request.|
Enter the byte timeout in milliseconds to wait for the last byte of a packet.
The Demark Timeout is used to help identify the end of a packet after the RediGate has started receiving bytes on the serial port.
|Error Check||Select the error check type (BCC, or CRC-16).|
A Network Circuit is an IP network communications path to one or more field units from a common Master Channel. The Network Circuit is used when the field unit is connected to the RediGate over a TCP/IP network.
See the RediGate Configuration Manual for information on configuring the NetCircuit object.
If using a Df1Rs232circuit for serial DF1 devices, make sure to include a COM port (System>Networks>AsyncPort) object in the configuration with the instance number matching the physical COM port, and the baud rate corresponding to the field device’s setting.
See the RediGate Configuration Manual for information on configuring the AsyncPort.
A DF1 or CSP Field Unit object contains unique information for each Field Unit using the Allen Bradley PLC communication protocols, and defines parameters for how data is read and written for the device.
|Poll Table Properties|
Enter the starting source register in the DF1 (or CSP) device to begin polling data. This will be found in the documentation for the device, based on the information that you want to obtain. This field should be set the same in each row of a "continuation poll." The DF1 Address should be entered in one of the following formats, based on the PLC Addressing Type (below):
|PLC Addressing Type||Select the PLC addressing type of the DF1 Address entered in the previous column (above). This field should be set the same in each row of a "continuation poll."|
PLC-5 Logical Binary
PLC-5 Logical ASCII
Select the data type of the data being read in this row of the Poll Table. If the Read Count of points contains data of different types, use multiple rows to define the number of points to read for each Data Type and the Destination Register in which to store each set of data. Select the data type from:
|Read Count|| Enter the count of points to read from the device. |
If polling for a block of data from a single "file" with different Data Type and/or Destination Register range, use multiple rows in the Poll Table.
The Read Count on the first row of a continuation poll should include the total number of registers to include in the DF1 protocol request, with the Write Count defining how many points of a specific data type to save into the RTDB.
Set the Read Count to zero (0) on subsequent consecutive rows of the same poll definition, to indicate a "continuation poll."
|Write Count||Enter the count of points to store into the RTDB Destination Register. |
If polling for a block of "file" data with different Data Type and/or Destination Register range, the Read Count is set to zero (0) on all rows after the initial row of the "continuation poll."
In all cases, the Write Count should include only the count of points to parse from the message using the Data Type specified on this row. The data will be stored into the RTDB, beginning at the RTDB Destination Register. Include as many rows as needed to parse data from the poll message, with Read Count=0 and Write Count set to parse the data type.
If parsing data using the "Bit" type, the count must be the number of binary bits. If parsing the data using the "Integer" type, but storing into Boolean registers, the Write Count must be the number of integer registers to be parsed—but be aware that 16 bits per integer register will be stored into the RTDB.
|RTDB Destination Address||Enter the starting destination register within the field unit's RTDB into which the Write Count of data points will be stored. These registers must be configured in the RTDB object.|
The Destination Register type should be chosen based on the Data Type of the data points defined on this row of the Poll Table.
Bit data should be stored into Boolean RTDB registers.
Integers should be stored into 16-bit RTDB registers. It is also permissible to use the Integer data type but store into an RTDB Destination Address that is defined as a Boolean. In this case, each of the 16 bits of the integer will be stored sequentially into the RTDB, beginning at the least-significant bit.
Floating point data should be stored into REAL32 RTDB registers.
Example of Continuation Poll
As an example of a continuation poll, assume that the DF1 PLC has statuses, accumulators, controls, and setpoints all packed into different boards located at $N9:60 through $N9:119 registers (using PLC-5 Logical ASCII format). Below is an example poll table with this information.
Rows 6 and 7 may be included as entries in the Master Channel's Scan Table, but only if the RediGate needs to read the binary control bits and analog setpoint values from the PLC continuously. If it is only necessary for a host system to write to these control registers (not read the feedback)—for instance, if the control feedback is obtained from reading other DF1 registers—the Poll Table definitions are still required in order to map Modbus RTDB registers to DF1 device point numbers, but there is no need to include Scan Table entries for these polls (see Master Channel on page ).
See the RediGate Configuration Manual for information on configuring the RTDB.