Process change: New tuning required?
Process change: New tuning required?
(OP)
We just increased the size (HP, thus flow and pressure) of our cooling water pumps.
We have several users, each controlling the amount of cooling water to themselves with a control valve (all temperature control) - approximately 10 users.
Because of the increased pressure/flow, do we have to re-tune each of the user's cooling controllers due to the change in process conditions? Or should the existing tuning suffice?
If we need to change, can you explain why? Shouldn't the existing controller determine that it needs more or less cooling and thus change the valve output "as-is"?
We have several users, each controlling the amount of cooling water to themselves with a control valve (all temperature control) - approximately 10 users.
Because of the increased pressure/flow, do we have to re-tune each of the user's cooling controllers due to the change in process conditions? Or should the existing tuning suffice?
If we need to change, can you explain why? Shouldn't the existing controller determine that it needs more or less cooling and thus change the valve output "as-is"?





RE: Process change: New tuning required?
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One day my ship will come in.
But with my luck, I'll be at the airport!
RE: Process change: New tuning required?
RE: Process change: New tuning required?
However, if you increased the head signicifantly, or your valves are sized on very low delta P's so that your new head is a significant percentage differance of your sizing delta P, you should re-tune.
rmw
RE: Process change: New tuning required?
The existing tuning is undoubtedly not perfect, and there are non linearities all over the place (control valves, pump response etc) so the loops are probably on compromise settings anyway.
If the loop is still stable and is fast enough then why change it?