Configuring a Modbus Server

Modbus Server is a function in EPM Data Management that exposes device data to external Modbus TCP clients through an automatically generated register map, so other systems can read and write supported values.

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

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

The Comms Link screen displays:

Select from the following options to expand the details:

  1. From the left-hand side of the Comms Link screen, select Add .

  2. 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.

  1. From the left-hand side of the Comms Link screen, select Modbus Server 1.

  2. 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.

  3. Complete the configuration as required:

    • Type - Displays the device's role on the Modbus network, cannot be updated.

    • Descriptor - Defaults to 'Communication type n' where n is the next number in sequence from the previous Comms Link. Enter a unique name for this Comms Link to identify it if required.

    • Modbus Type - Displays the communication protocol variant, cannot be updated.

    • Port Number - Displays the TCP port used for Modbus communication. Defaults to 502. 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 integrated when exchanged over Modbus.

      • Scaled - Values are transmitted as integers that represent scaled engineering units.

      • Float32 - Values are transmitted as 32-bit floating point numbers.

    • Default String Terminator - Defines how text strings are ended when sent over Modbus.

      • Null Terminated - String ends with 0ˣ00 byte.

      • Space Packed - String is padded with space characters 0ˣ20 untill 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.

 

Related topics - Comms Link, Deleting a Comms Link, Exporting a Modbus Address Map, Deleting a Modbus Address Map