Modicon PID2 Hold!

[darrenj]

I am looking to hold a value in a PID loop.
The application is i am running x amount of liters through a flow meter...my loop is perfect and i am flowing bang on...the system goes into recirc mode..meaning i dont want any of my liquid to flow..so my valve closes and my pump shuts down...now it goes out of recirc mode and it takes a min or two for the PID loop to fall in line..meaning i could get 30l per min rather that 15 l per min for a little bit...
what i would like to do is close the valve but keep the drive running at the same speed...so now my flow rate would be 0 but i want to freeze the 4x register going to the analog out..

any suggestions?

 

[MRobert]

The address that shows this recirc mode have to do the following :
1. A contact changes the PID to manual mode (upper input). This action freezes the PID output.
2. A contact connects a block that writes zero to the Analog Output (0 minus 0 -> AO). This block have to be AFTER the block that copies the PID output to the AO. (a network after or in the RIGHT of the block that copies the PID to AO).
To go back to normal operation open both contacts.
Robert