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Just ended up converting a Kamyr digester from Foxboro I/A to Honeywell Experion PKS. The issue we are currently facing in our diffuser process is the upstream controller output initializes to a reset value (say 60% to 40%) every time our process cycles/strokes.
The OP of this block is tied to the SP of a Ratio control block, whose output then feeds to another PID block which then feeds into an AO channel.
We have secondary initialization enabled on the block, but haven't been able come up with any sort of hold to prevent the block from resetting each time the process cycles (approximately every 80 seconds). When the process does cycle, the AO channel (an auto valve) is moved from its current position, down to zero, and then back to its last position.
I know in Foxboro I/A there was a HOLD parameter that we could end up tying logic to, but I am not familiar enough with Honeywell's blocks to be able to identify how to accomplish what we want here. A fellow coworker mentioned the use of a PIDER block as a potential solution, but I wanted to pick a couple other brains to see if we are missing anything.
<b>Moderator's Note:</b> check out thread http://control.com/thread/1460919246
The OP of this block is tied to the SP of a Ratio control block, whose output then feeds to another PID block which then feeds into an AO channel.
We have secondary initialization enabled on the block, but haven't been able come up with any sort of hold to prevent the block from resetting each time the process cycles (approximately every 80 seconds). When the process does cycle, the AO channel (an auto valve) is moved from its current position, down to zero, and then back to its last position.
I know in Foxboro I/A there was a HOLD parameter that we could end up tying logic to, but I am not familiar enough with Honeywell's blocks to be able to identify how to accomplish what we want here. A fellow coworker mentioned the use of a PIDER block as a potential solution, but I wanted to pick a couple other brains to see if we are missing anything.
<b>Moderator's Note:</b> check out thread http://control.com/thread/1460919246