Rockwell Automation 20-COMM-M Modbus/TCP Adapter - Manual (Page 39)

Using Modbus/TCP Function Codes 4-3
20-COMM-M Modbus/TCP Adapter User Manual
Publication 20COMM-UM014C-EN-P
Using Function Code 43 to Read Drive Identification
Function Code 43 enables you to read the drive’s vendor name, product
code, and major/minor firmware version. To do this, always set the
following Modbus/TCP transaction elements to these values:
Using the I/O On Modbus/TCP, data transfers are used to transfer the I/O data that
controls the drive and sets its Reference. Note that output I/O is data that the
master device sends and the adapter receives. Input I/O is status data that the
adapter sends and the master device receives.
Important: To enable the drive to use the I/O and Reference from the
Modbus/TCP network, you must set parameters in the drive to
receive the I/O and Reference. For details, refer to
Configuring/
Verifying Key Drive Parameters on page 2-8 .
Keep-Alive Register (Address 10002)
The Keep-Alive register enables you to reset the adapter’s internal
communication loss timer to the value stored in adapter Parameter 19 -
[Msg I/O Timer]. A decimal value between 0 and 65535 can be written to
the Keep-Alive register address 10002 to reset the timer. This value is not
stored and does not affect any data transaction. It is a convenient way to
reset the timer without writing to the Logic Command, Reference, or
Datalink (Data In xx) words.
Important: To establish communication between the controller and drive,
you must write a positive non-zero value to the Keep-Alive
register address 10002. Furthermore, that value must be written
to register address 10002 more frequently than the timeout
value stored in Parameter 19 - [Msg I/O Timer] to avoid a
communication loss. For example, if parameter 19 is set to 5
seconds (default), write a value to register address 10002 every
4.9 seconds or less.
4 DPI Port 4 (peripheral connected to Port 4 of a four-way splitter cable)
5 DPI Port 5 (peripheral connected to the drive’s internal Port 5 or to Port 5 of a four-way
splitter cable)
6 DPI Port 6 (reserved for future use)
7…15 Reserved for future use
16 DPI Port 0 (Drive) — an alternate to using Unit Identifier 0
17…254 Unused — defaults to Unit Identifier 0
255 Adapter
Modbus/TCP Transaction Element Required Value (Decimal)
Unit Identifier 0 (zero) or 16
MEI (Modbus Encapsulated Interface) 14
Read Device ID Code 1
Object Id 0 (zero)
Unit
Identifier Device Connection (Example)