Modbus TCP-IP Server (Slave) commissioning

FX substation Modbus TCP-IP Server activation

Modbus addressing can be 0-based or 1-based which means that first register can be either number 0 or 1. This is totally manufacturer dependent and should be displayed in manual of connected device. Fidelix Modbus addressing is 0-based.

Modbus TCP-IP Server (formerly Slave) feature can be activated with following steps: 

  1. At the Settings -> Activations check if your FX substation version supports Modbus TCP-IP server feature. 


    If no record found, please update your FX substation to the version 12.30.06 or newer.
    support.fidelix.fi

    Go to the https://activations.fidelix.com and enter "Product code" from Modbus Server record line.

    Enter received activation key (6 symbols) to the "Activation key" field and press "Change" button. Check if "Product activation OK" appears. 

  2. To enable communication over Modbus TCP-IP, go to the Settings -> Ports. From there select any of ports between 6..10 and set it to "Modbus TCP". Set the sending delay as short as possible. You can start at 0 and increase it depending on how modbusdevice seems to be communicating. Network or device can be bit slow and thus increasing send delay could help. The slower the Modbus TCP-IP Server system, the higher value it should be. The "send delay" is always waited before sending packet. Press "Change" to save changes. 

  3. Make sure that modbus Client-device (Modbus TCP-IP Master) IP address is in the same IP subnet as the FX substation. If using FX3000-C, FX-SPIDER-40/10, check if Device is connected to proper LAN or WAN network.

    Example:
    FX3000-C with Device connected to LAN. 
    Set Device  IP to 192.168.11.101
    Set Device Default Gateway to 192.168.11.1
    Set Device subnet mask to 255.255.255.0

  4. Check the Device register requirements and create corresponding Modbus device:
    Programming -> Modbus devices
    E.G. if in the OpenPCS interface (documentation) is following: CREATE MODBUS DEVICE: HOLDING REGISTERS, STARTING REGISTER: 201, NUMBER: 64 

1. Select port previously set to "Modbus TCP"
2. Set Modbus device address on the port 1..255. Applicable if several Modbus TCP-IP servers are connected on the same port. By default, Fx communicates via IP-address.
3.4.5. Select register type, start register and register count. 
In Fx-system, Start register uses Data Addressing model in decimal format, for example:
Holding reg number 40001 (first holding reg, HEX 0000) is in Fx-system start reg 0.
6.7. Set TCP/IP module, IP address, and IP port (Default is 502) belonging to the Device.
8.9. Check that communication is established. Communication works if "Messages Total" is bigger than zero and some values are shown in the table below and "Communication ok" message was shown.

Now the FX substation is communicating with Modbus TCP-IP and ready for transferring register values to points using IEC program.

 

Article updated 24.01.2023