Experimental Physics and
Industrial Control System

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<== Date ==>		<== Thread ==>

Subject:	RE: Misunderstanding of epid record ODEL field?
From:	"Mooney, Tim M." <[email protected]>
To:	Peter Linardakis <[email protected]>, "[email protected]" <[email protected]>
Date:	Wed, 22 Apr 2015 14:37:25 +0000

Hi Peter,

In the meantime, you could drive the motor through a calcout record, like this:

epid writes to suppress.A

record(calcout, "suppress") {
    field(INPC, "epid.ODEL")
    field(CALC, abs(a-b)>c")
    field(OOPT, "When Non-zero")
    field(DOPT, "Use OCAL")
    field(OCAL, "b:=a;b")
    field(OUT, "motor PP")
}

Tim Mooney ([email protected]) (630)252-5417
Software Services Group (www.aps.anl.gov)
Advanced Photon Source, Argonne National Lab

From: [email protected] [[email protected]] on behalf of Peter Linardakis [[email protected]]
Sent: Wednesday, April 22, 2015 1:08 AM
To: [email protected]
Subject: Misunderstanding of epid record ODEL field?

Hello techtalkers

I am trying to control a motor that drives a slow tuner based on phase and/or amplitude error signals. It’s still just in testing but the basic control works. However, The motor seems to attempt to move on every iteration of the epid loop, even if the magnitude of the epid.OVAL field is less than the epid.ODEL field. Do I understand the intention of the ODEL field correctly? I’d rather not have the motor try to move on every loop iteration. The relevant records are below:

record(calc, "$(res):$(ta):tuning_error") {

field(DESC, "Overall tuning error")

field(INPA, "$(res):$(ta):phase_error")

field(INPB, "$(res):$(ta):ampl_error")

field(CALC, "B-3*A")

}

record(epid, "$(res):$(ta):tuner:control_pid") {

field(DESC, "PID loop to control tuner postion")

field(INP, "$(res):$(ta):tuning_error CPP")

field(SCAN, ".1 second")

field(SMSL, "supervisory")

field(VAL, "0")