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

Subject: RE: Misunderstanding of epid record ODEL field?
From: Peter Linardakis <[email protected]>
To: "Mooney, Tim M." <[email protected]>, "[email protected]" <[email protected]>
Date: Thu, 23 Apr 2015 00:59:57 +0000

Thanks to both Tim and Mark…

 

A modified version of what Tim suggested below did the trick (didn’t need the OCAL field as I’m driving the motor using the .RLV field)

 

Regards

Peter

 

From: Mooney, Tim M. [mailto:[email protected]]
Sent: Thursday, 23 April 2015 12:37 AM
To: Peter Linardakis; [email protected]
Subject: RE: Misunderstanding of epid record ODEL field?

 

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")

  field(OUTL, "$(res):$(ta):tuner:motor.RLV PP")

  field(FBON, "1")

  field(MDT, "5")

  field(KP, "-0.12")

  field(KI, "0")

  field(KD, "0")

  field(EGU, "mm")

  field(ODEL, "0.04")

  field(DRVL, "-1")

  field(DRVH, "1")

  field(DISV, "0")

  field(SDIS, "$(res):$(ta):tuner:mode CPP")

}

 

Thanks in advance

Peter

 

Dr Peter Linardakis

Accelerator Research & Development Engineer

Nuclear Physics | Research School of Physics and Engineering

Australian National University

e: [email protected]

p: +61 2 6125 2862

w: http://physics.anu.edu.au/nuclear/

 


References:
Misunderstanding of epid record ODEL field? Peter Linardakis
RE: Misunderstanding of epid record ODEL field? Mooney, Tim M.

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