MODBUS over TCP/IP using M12 Ethernet Port

Powervision has a separate MODBUS application which allows communications over Ethernet TCP/IP on the M2/G1e processor based displays. This is found in the Connections Tab.

Download the MODBUS TCP/IP Server Example

Download the MODBUS TCP/IP Client Example

Display Compatibility:

• Display must have the M2 or G1e family of processors.
• Must be a connected version of the display with the M-12 Ethernet connector. This can also work on the USB port using the USB/Ethernet adapters on displays with no M-12 connector however it is not a robust solution for field applications.

Powervision Configuration:

• Network Setup

  • In the System Manager Application -> Network tab, add a second network client connection with a unique IP address with a different subnet than the default USB network.

 

• MODBUS Setup

  • Configure the MODBUS TCP Port - in the Connections tab select Modbus TCP Port then select Server or Client mode. The Server will behave as a slave device responding to Poll requests from a Client.

• Device Setup

Server -

• • The default IP address created in the Network settings will be used. The default port is set to 502 which is the industry standard for Modbus TCP/IP.
  • The Unit ID is ignored in TCP/IP mode so the Client can use any ID when polling the display.

• • Add the registers needed for the application.
  • In the programming tab find the variables that were created in the previous step and deselect the allow invalid checkbox otherwise the value will go to 0 if the variable is not continually updated.

Client -

• • Add a Device for each of the devices on the network.

• • Set the IP address of the Remote Server  to poll data from, the Port number will be 502 for MODBUS.
  • Set the Unit ID of the device you are polling. Multiple devices can be added to the list.

• • Add a Mapping group and select if you are reading registers from the server or writing to them as well as the polling rate.

• • Add the desired registers and register type, the variables will be automatically created. These can then later be changed to existing variables if desired by de-selecting Auto Create.

• Mapping MODBUS Registers Additional Information- See MODBUS Article

• Programming

  • Create a User Event to call the action System->SwitchNetwork(name of new network), this will switch connectivity from the default USB network to the newly created network.
  • The application will automatically send out polling requests or respond to polling requests base on the polling rates selected without intervention.

 

Computer setup:

• Use the Ethernet port embedded on the computer, if using a laptop do not use the Ethernet port on the docking station. Connection to a Ethernet switch connected directly to the computer will also work.
• Change the computers Ethernet Port IP address to match the displays new network IP subnet address. The lowest number should be a different value than the other devices on the network. 
• Select IP Version 4 and set the IP address to the desired subnet with a mask of 255.255.255.0. Leave the Gateway entry blank.

Cabling Example used for Testing:

• M12 A-Coded 5 Position cable Enovation part # 78051576 converted to RJ45 on one end using RJ45 to 8 Pin Terminal Block adapter.

Testing

• Load the MODBUS Server example configuration on a display.
• Connect the display M12 Ethernet port to a computer or through a switch.
• In Powervision change the connection settings to match the M12 Ethernet port settings.

• Select the M12 Port after the display boots up. The Ethernet port lights on the switch or computer should start flashing. If the connection fails make sure the computers Ethernet port has been configured with the same IP subnet address.
• Use MODBUS emulation software on the computer to poll the display configured as a MODBUS Server.
• Use Wireshark to monitor activities on the Ethernet bus.