PLC-DCS switchover by soft button

[jainil2210]

I have AB PLC with 1756-L72 controller and Chessis I/O for one of my job with panel view plus 1250 and control net communication.
PLC is communicating to Emerson DCS over ethernet.
DCS is master.

My requirement is with a single soft push button in HMI (Local-Remote), how I can switch over control to/from PLC to/from DCS ??

When, soft switch in local mode, HMI should write data to PLC and DCS can not write data to PLC (including set point, PID control and all), DCS will be view only.

When soft switch in Remote mode, DCS will control PLC and HMI will be view only except that soft switch and in this case HMI setpoint entries and other controlling parameters will track DCS data.

Is this possible??Please help me on this.

 

[JeffKiper]

I would use something that someone else can understand.
If Mode remote MOVe A to B
Else MOVe C to A

This can be read and understood by others. I think if you do something like disable the ControlNet connection from the HMI. It could be extremely hard to troubleshoot for someone not up to speed on advanced communication setups.