Comtrol Modbus TCP User Guide - Manual (Page 76)

76 - Chapter 5. Alias Device ID Functionality DeviceMaster UP Modbus/TCP User Guide: 2000447 Rev. I
Overview
The functionality is described in the following diagram:
Note 1: These are the originally received Modbus messages. All responses will be returned with the original
device ID.
Note 2: Modbus messages sent to and responses received from Modbus Message Routing Handler.
Depending on the Alias Device ID configuration, these messages may contain the originally received
device ID or the alias device ID.
Note 3: The Alias Device ID functionality does not apply to raw/ASCII data received from Ethernet TCP/IP
application connections.
Note 4: The Alias Device ID functionality does not apply to Modbus/TCP slaves when a raw/ASCII serial or
Ethernet TCP/IP device is set to Master Rx and/or Tx mode. This is when the DeviceMaster UP is
writing or reading raw/ASCII data from the Modbus/TCP slave device’s memory.
Note 5: Modbus messages received from the Modbus Message Routing Handler and sent to Modbus slaves.
Depending on the Alias ID configuration, these messages may contain the originally received device
ID from the Modbus master or the alias device ID. All responses contain the device ID as received
from the Modbus Message Routing Handler.
Note 6: Serial raw/ASCII devices must be addressed with a device ID of 255. The device ID of 255 may be
either in the original message or derived from the alias device ID configuration.
Note 7: Ethernet TCP/IP raw/ASCII devices must be addressed with a device ID of 254. The device ID of 254
may be either in the original message or derived from the alias device ID configuration.
Alias Device ID Functionality