EPICS Controls Argonne National Laboratory

Experimental Physics and
Industrial Control System

1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  <20142015  2016  2017  2018  2019  2020  2021  2022  2023  2024  Index 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  <20142015  2016  2017  2018  2019  2020  2021  2022  2023  2024 
<== Date ==> <== Thread ==>

Subject: RE: ePID deadband on output
From: "Mooney, Tim M." <[email protected]>
To: Bruce Hill <[email protected]>, "Dalesio, Leo" <[email protected]>, "[email protected]" <[email protected]>
Cc: Core-Talk <[email protected]>, "[email protected]" <[email protected]>
Date: Tue, 26 Aug 2014 16:56:42 +0000
By the way, this is Mark Rivers' record, in the synApps std module.

I was playing with the algorithm using calcouts and the StripTool, and I think it migt be frustrating for end users, because the effect of AIIR changes with the rate at which the algorithm is run.  For example, the phase lag in FERR doubles when you halve the rate at which new readings are processed.  Maybe this is desirable from some viewpoints, but it will confuse people.  The epid record includes the time between readings in its current algorithm (see http://www.aps.anl.gov/bcda/synApps/std/epidRecord.html#Feedback%20Parameters), and I think many end users would like this also in the proposed filter.

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 Bruce Hill [[email protected]]
Sent: Tuesday, August 26, 2014 2:38 AM
To: Dalesio, Leo; [email protected]
Cc: Core-Talk; [email protected]
Subject: Re: ePID deadband on output

Not my call, but we have been happy with the approach we used as it
gives independent control over the auto-on threshold, the auto-off threshold,
and the error filter factor which determines how sensitive the auto on/off is to
noise and transient conditions such as moving through the target point.

If people like this approach, the fields could look something like this:
AIIR - The auto on/off IIR filter factor
AON - The auto on error limit
AOFF - The auto off error limit
AUTO - Auto mode on/off
FERR - Filtered error

FERR = ERR * (1.0 - AIIR) + FERR * AIIR
if (AUTO && ABS(FERR) <= AOFF)   FBON = 0
if (AUTO && ABS(FERR) >   AON)    FBON = 1

Cheers,
- Bruce

On 8/25/2014 4:43 PM, Dalesio, Leo wrote:
> Did the conversation converge on a solution?



References:
ePID deadband on output Pearson, Matthew R.
Re: ePID deadband on output Benjamin Franksen
RE: ePID deadband on output Mark Rivers
RE: ePID deadband on output Dalesio, Leo
RE: ePID deadband on output Mark Rivers
RE: ePID deadband on output Dalesio, Leo
Re: ePID deadband on output Pearson, Matthew R.
Re: ePID deadband on output Bruce Hill
Re: ePID deadband on output fong
Re: ePID deadband on output Bruce Hill
RE: ePID deadband on output Dalesio, Leo
Re: ePID deadband on output Bruce Hill

Navigate by Date:
Prev: RE: synApps record Mooney, Tim M.
Next: Re: synApps record priya tiwari
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  <20142015  2016  2017  2018  2019  2020  2021  2022  2023  2024 
Navigate by Thread:
Prev: Re: ePID deadband on output Bruce Hill
Next: pyepics problem with PV.put(wait=True) Jameson Graef Rollins
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  <20142015  2016  2017  2018  2019  2020  2021  2022  2023  2024 
ANJ, 17 Dec 2015 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· Search · EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·