Modbus TCP Uncaught Throwable - PV1200

Ignition
1

Current Ignition Version: 8.1

We have several remote sites in an area that all talk over 900 MHz Ethernet radios (MDS iNet 900) to an access point. If we ever lose comms for any reason (power issue, etc.) and they come back, all of our devices in the field will start communicating again except for one in particular. This one device in particular is a California Motor Controls PV1200 pump controller. It's really a Unitronics 1210 PLC+HMI combo that has proprietary programming built in. Ignition communicates with this controller via Modbus TCP. It is worthy to note that all of the other remote devices are a combination of SCADAPack32 and Micro 850 PLCs all communicating via Modbus TCP, and they have no issues.

I have replaced the PV1200 and the radio at the site but no luck in resolving the error. The downside is that I cannot see the programming in the PV1200 to see if the controller is throwing errors so I have to go off what Ignition can provide me.

I'm hoping someone may be able to point me in the right direction to find out what the issue is and if the logs I have included are pointing to the cause of the reconnection issue.

I have included a snapshot of log errors related to this driver connection.

Capture
Capture1181×619 132 KB

2

You should try to get a wireshark capture. The screenshot suggests that the target device is not obeying the rules for Modbus TCP framing.

1 Like
3

Mr. Turmel

Thank you for the reply. We have tried every setting in the controller to alleviate the issue. Unfortunately, I cannot see the backend as the program is proprietary. I have installed a Micro 850 controller that polls the Modbus data from the PV1200 via RTU (RS485) and then passes that data on to Ignition over Modbus TCP. The RTU polling doesn't miss a beat and even when the PV1200 quits passing Modbus traffic to Ignition, the Micro is still able to get the Modbus data and pass it to Ignition via Modbus TCP.

I have reached out the manufacturer about the issue but have not heard back. We have TCP devices all over our network and have never had this issue. I'm really interested to see if anyone else are using these controllers. If so, are they having the same issues.

4

You might try the IA driver's Modbus RTU over TCP with an Ethernet-to-RS485 converter (I like Moxa products for this), or my alternative driver for the same. I would expect that to be notably cheaper than the Micro850.