FX2N PLC Integration with 2 Weintek HMI.

[sultanahmed]

Hello everyone,

I am currently facing a challenge while trying to connect two Weintek HMI units with a Mitsubishi FX2N PLC. When connecting a single Weintek HMI using the 4-wire RS-485 interface, everything works perfectly. However, when attempting to connect a second HMI in a multi-drop configuration on the same 4-wire RS-485 interface, both HMIs seem to malfunction. I've tried changing the HMI station numbers, but the issue persists.

FX2N PLC only has a single available port. I'm seeking advice on how to successfully connect two HMIs to the FX2N PLC. Any guidance or suggestions would be greatly appreciated.

 

[the_msp]

What model of Weintek? Some Weintek's offer the capability to serve data to other HMIs' (Remote Station)

 

[sultanahmed]

Existing HMI is 8102ip. I know the feature of remote Hmi configuration.
My reservation for this is to lay ethernet cable which is not posible.
I already layed 485 cable for both hmi.

 

[Steve Bailey]

What protocol does the HMI use to communicate with the PLC? I suspect the problem lies with two masters (the HMIs) trying to communicate with a single slave (the PLC). What you are trying to do may not be possible with the protocol you're using.

 

[sultanahmed]

Hello.
I am using FX2N default protocol using RS485 configuration.

 

[Steve Bailey]

Upon looking at this manual:
https://dl.mitsubishielectric.com/dl/fa/document/manual/plc_fx/jy992d69901/jy992d69901e.pdf
I come to the conclusion that the protocol does not support what you're trying to do. In Mitsubishi's terminology, the protocol supports 1:N connection where the "1" device is the HMI client and the "N" represents up to sixteen server PLCs communicating with a single client. You are trying to implement a 2:1 configuration which is two clients trying to communicate with a single server. The protocol does not appear to have any provision to arbitrate collisions between requests from the two clients.