Hardware manual

AB PCCC Server Impact Reference Guide
Datalogic Automation Inc. 2-40
How VPM Works With Modbus TCP/IP
The Modbus server runs continuously on the Impact device, listening on the standard Modbus port 502. It
does not initiate any communications, but waits for other Modbus devices on the network. To configure a
VPM task to run when a Modbus device communicates with the Impact device, select the Modbus Event
Trigger Event Type. To run it when Modbus register data changes, select Modbus New Input Data Event
Trigger Event Type. (See “Trigger Event Types” on page 3-35).
The server supports only Conformance Class 0 functions — Read Multiple Registers (Function Code -
0x03) and Write Multiple Registers (Function Code - 0x10). There is one register address space starting at
address 0. All Modbus registers are 16 bit integers and the most-significant bit (at the lowest address) is sent
first (known as Big Endian).
Read and Write a Modbus Register
Since VPM tool property values cannot be directly linked to a Modbus register, you need to use a Data Set
tool to push a value from a tool’s property into the register. Register values can be directly linked to a VPM
tool property.
How to write to a register
1. Place a Data Set tool in the task.
2. In the Data Set tool, click the create link button on the Destination Port, then select the desired Modbus
Register.
3. In the Data Set tool, click the create link button for the Value property, then select the property you
want to link from the source tool.
4. When the Data Set tool runs, it pushes the desired value into the Modbus Register.
How to read from a register
1. In the desired tool, select the desired property.
2. Click the create link button.
3. In the Modbus Server system object, select the desired Modbus Register.
4. When the tool runs, it reads the desired value from the Modbus Register.
AB PCCC Server
The AB PCCC Server allows Allen-Bradley®, Rockwell Automation®, and compatible PLC devices to
exchange data with Impact devices using the Programmable Controller Communication Commands (PCCC)
protocol encapsulated inside EtherNet/IP commands. The PCCC format is compatible with the Allen-Brad-
ley standard PLC-5 which is supported by a wide variety of their PLCs including the SLC™-5, PLC-5®,
and later products. There are brief details of the server’s operation after the following table.
Trigger Ack [33] If the Trigger register value is set to non-zero, the camera is triggered
and that value is also written to this register as a trigger acknowledge-
ment.
Reserved [34] - [63] These registers are reserved for future use
Register [64] - [127] The Modbus client can write to these registers.The value in the register
can be linked to VPM tool property values.
Input Name What it is