Configuring a Modbus Server

Modbus Server in EPM Data Management exposes device data to external Modbus TCP clients through an automatically generated register map.

Note - You can only access this function if you have the Can access Communications Link permission. To update settings you must also have the Can edit Communication Link permission. If you need to access these functions and do not have permission, please contact your system administrator.

From EPM Device User Interface screen, select Options - Device I/O - Comms Link:

Select from the following options to expand the details:

Configuring a Comms Link

From the left-hand side of the Comms link screen, select the Modbus Server required:
If you are not already in Configuration lock, the Configuration lock screen displays:

Enter a reason if required and then select Confirm . The system configuration is now locked pending the submission of your update and the Configuration Locked icon displays on the status bar.

Note - Configuration lock does not affect the operation of the EPM device.

See Configuration Lock for details.
Complete the configuration as required:
- Type - Defaults to 'Modbus Server'. This option cannot be updated.
- Descriptor - Defaults to 'Modbus Server n' where 'n' is the next number in sequence from the previous Modbus Server. Enter a unique name for this communication link to identify it if required (maximum characters 40).
- Modbus Type - Defaults to 'Modbus TCP'. This option cannot be updated.
- Port Number - Displays the TCP port used for Modbus communication. Defaults to '502' the standard port for Modbus TCP. Enter a valid port number or use the Plus or Minus to allocate the correct port. (Lowest 1, highest 65535).
- Default Numeric Format - Defines how numeric values are exchanged over Modbus. See Understanding the Modbus server address Map for details:
  - Scaled - Values are transmitted using one register as a scaled 16 bit integer.
  - Float32 - Values are transmitted using two registers as Institute of Electrical and Electronics Engineers (IEEE) 754 32-bit floating point numbers in engineering units.
- Default String Terminator - Defines how text strings end when sent over Modbus. See Understanding the Modbus server address Map for details:
  - Null Terminated - String ends with American Standard Code for Information Interchange (ASCII) null 0x00 byte.
  - Space Packed - String is padded with ASCII space characters 0x20 until the full register length is filled.

Once complete, select Review pending changes screen to review updates to the configuration, and submit them. See Reviewing and Submitting Changes for details if required.

Note - Reviewing and submitting can be completed in bulk once you have completed all your additions and/or updates.