Check connection between M241 and generic modbus TCP slave

[dmuzina]

Hello,

I have Modbus TCP/IP connection between schneider M241 PLC and Delta C2000+ VFD (PLC is master) and I want to be sure that connection is working all the time. Do I have some bit or can I implement some logic to always check that connection is working all the time?

Thanks

[Bastian_Schmitz]

How do you set up the communication? Via FBs (Read_var/Write_Var) or via IO Scanner? If you use the FBs you should able to see the status of the FBs. Otherwise you could check the communication via integrated system variables which you could find in the online help. 

Link

[Dotzauer]

Hello, I have similar problem with multiple VFD. I found:

https://product-help.schneider-electric.com/Machine%20Expert/V2.2/en/ESMEModbusTCP/index.htm#rhfulll...

Is this good solution?

[FernandoRodrigues · Accepted solution]

Hello,
If you are using IO scanner, for ModbusTCP, there is available Healthbit for each channel. If TRUE, channel is running and exchanging data.

[dmuzina]

Hello, we have problem with communication between M241 and Delta VFD. When we power off PLC and again power ON We don't have those Health bits turned ON, maybe few. We have 19 Health bits for 2 VFD and after power On PLC we have 3 or 4 of 19 turned ON. And solution is that we read multiple times (10 times) registers on VFD with program from delta and after each reading we get some health bits ON and after 9 or 10 times we get all health bits ON. That is only solution we could find to solve that problem but after power OFF PLC and power ON we again have that problem. Some have some solution?

[dnordenberg1]

Sounds like you are overloading the VFD with more requests than it can handle. If you have to read on a lots of places you might have to do a "round robin" scheduler that trigger each request in sequence one or a few at the time.