Ignition Perspective, Toggle Button - Status of button in relation to PLC tag initial deployment

Ignition
1

All,

I have a system critical application where I cannot afford to cause a shutdown.

I want to add a toggle button to enable an input for valve(s) close/open position feedback. My issue is that this is going to be using a UDT and global object used by all valves. I have the toggle added and the UDT added but I have not yet deployed as I was not sure if the toggle's state will override the PLC when I first deploy the change or if the PLC will override the Ignition perspective page toggle button.

Half of my valves have this open/close proximity switch input and the other half do not so I want the current PLC status to stay the same when I deploy this to avoid adverse effects on the system. If ignition overrides my PLC I would have to go through and toggle all the valves and this could shut many parts of the process down due to the associated alarming.

So my question is if the toggle status in ignition will update from the PLC or will it update to the PLC when first deployed.

Kind regards,

2

This should already be a known. And it hints at a larger problem. Tags should not be written to from two directions, this will lead to race conditions. Either the PLC controls the state, or Ignition does, not both.

There is no way any of us will be able to answer your question as we do not have access to your PLC logic or Ignition project which would be the minimum required to even begin.

The common approach would be to have the toggle request a state, and the PLC logic should be written in a way that it decides when it is appropriate to allow that state change.