Can an HMI with CODESYS communicate with an AB PLC?

Codesys & I/O Q&A
Can an HMI with CODESYS communicate with an AB PLC?
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(CMT-3162x)
I have a spare HMI that we enabled Codesys on to test out if we wanted to used Codesys for future projects. We decided against it and would like to use the HMI as a replacement part for another project. The other project does not use Codesys and instead uses an AB PLC. I saw on the FAQ that you cannot deactivate Codesys and I see that the two ENET ports are now configured to work as a dual port output. Is there any way to configure the HMI to work with a AB PLC at this point?

2

Hi @agoodman,

Yes, your cMT3162X can still communicate with external PLCs like your AB PLC or connect to IIoT sources or databases using LAN 2. Essentially, all typical HMI related activity can be accomplished via the LAN 2 port when CODESYS is activated. However, since this unit has an active CODESYS license LAN 1 and the CAN bus port will be reserved for CODESYS.

HMI diagram
HMI diagram689×419 4.8 KB

3

Thank you for the reply. I was able to get the HMI to read from my PLC.

How does easy access work with this setup? I put both internet and the PLC on a switch and ran to the LAN 2 port. My PLC is on the address 192.168.124.101 and our usual HMI LAN address is 192.168.124.102 and the WAN port we set to discover automatically (DHCP) for easy access functionality.

With the Codesys enabled HMI, when I set LAN 2 to a static IP on the 192.168.124 network I can communicate with the PLC but cannot see the HMI on Easy Access. When I set LAN2 to DHCP I lose communication with the PLC but now can view on Easy Access.

4

Hi @agoodman,

To use EasyAccess 2.0 with LAN 2, the HMI must have an IP address that enables communication with both the PLC and the internet access point. If the access point’s gateway is, for example, 192.168.100.1, the HMI would need an IP in the 192.168.100.x range to communicate with it and, in turn, with EasyAccess 2.0.

However, maintaining a connection with the PLC may require changing the PLC’s IP to match the gateway’s subnet. Since this poses security risks, a better approach would be to use a managed switch or configure security settings within your router to safeguard the PLC from external access.

5

Thank you for the information, I will pass that along to our customers networking team and see if they are comfortable with that option.