RE: problem with EPICS pid record

[Mark Rivers <rivers@cars.uchicago.edu>]

>  I noticed this after the heater had maxed out at 200
> Watts, so I changed the PID max to 400 Watts.  The heater immediately
> jumped to over 600 Watts and continued rising.  I quickly 
> turned off the heater, or target damage would have resulted, but I was 
> really startled by the heater behavior.  Has anyone seen this behavior
before, 
> i.e. when the PID control maxes out it overcompensates when it come back?


I suggest your look at the EPID record, which has provisions for limits on
the output
http://millenia.cars.aps.anl.gov/software/epidRecord.html

Mark Rivers