Split range strategy help with Honeywell TPS

C

Thread Starter

Control_Bound

Hi all :)

Im sure there are numerous ways to achieve this. Im thinking about utilizing a RegPV'calc' point and inputing to two Regctrl'ratio' points (one 0-50 and the other 50-100), and then of course to the respective AO's.

If someone can help me out on this or at least point me to some online reference that detail good strategy building, I would really appreciate it.

thanks

T.
 
C

Control_Bound

OK, heres what I ended up with strategy wise:

Im utilizing the AI with each valve having its own respective Regpv(calc), Regctrl(ratio), Regctrl(pid), and then of course AO.

Im having a problem coming up with the respective equations to extract the split range personality. Can you help me wiht this? Also, if you see a problem with my strategy setup, feel free to criticise and make suggestions.

Thanks again!
 
one regpv'calc' point as the pv to one regctrl'ratio' point with the op going to one ao with the opin and opout linearized to 0-50 and 50-100 (assuming u split it at the field)
 
Hi T.,

You can also use one RegCtl writing to 2 analog outputs, just enable the output characterization (OPCHAR) on the AOs.

Set up the first AO as:
OPIN1=0.0, OPOUT1 0.0
OPIN2=100.0, OPOUT2 50.0

On the second AO, use:
OPIN1=0.0, OPOUT1 50.0
OPIN2=100.0, OPOUT2 100.0

You'll have to set up the RegCtl output limits at 0% to 100%, to avoid the default -6.9% to 0% and 100%-106.9% ranges. OPIN0 and OPOUT0 are set at those values and can't be changed. Use the OPFINAL parameter if you need to display each characterized output.

If the 2 analog outputs require differing logic for overrides or interlocks, they will need to have their own RegCtl point... JF
 
G

González, Gerardo

Hi T.

I have used split range with Honeywell TPS several times.
I assume you want to use a single control signal to drive two valves each having a full stroke of 0 to 100%. I also assume you are using HPM controller.

If this is the case, keep in mind that you don´t get initialization if you put a reg PV algorithm in the middle of a control strategy. This could be a problem on returning to cascade mode when you require manual individual operation of the valves. What I normally do is to push the signal from the controller into a couple of ratio control blocks and then by manipulating the constants in the ratio control algorithm (K1, K2, B1, etc.), I get the desired action.

This has the advantage of having the ratio control as a block that can be used to manipulate each valve in manual should that be necessary. Furthermore you have the option to back calculate control signal or ramp down the difference of signals when switching back to cascade. I do not recommend output characterization unless there is no other option. This could lead to confusion to operators and manual intervention on each valve becomes difficult.
I hope this answers your question.
 
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