I would like to keep as much of the logic in control studio the same, just incase they want things back to the original. I was thinking about just adding a CALC block, but I am unsure of what to actually do to make it easy for someone to troubleshoot and close the valve if need be. The operators will also NOT be able to change the Mode or SP. This is a standard OPEN/CLOSE valve. Can someone recommend a way to do this in a CALC block? I would like to keep the logic wiring if possible.
Your message is a little short on details, but in my opinion it is very dangerous to prevent operators from manipulating a piece of equipment, just in case there is an emergency of some sort.
I would suggest instead that you leave the mode selection up to the operator, but configure the DC1 block so that the Normal and Target modes are CAS. I would configure separate supervisory logic that drives the CAS setpoint of your valve module to the correct position to meet process conditions.
If you are just going to have a valve that is always open and can't be manipulated by an operator, it's hard to see why you even need a DC block.
Steve Elves
Process Control Technologist
In reply to AdrianOffield: