Experimental Physics and
Industrial Control System

Benjamin Franksen <[email protected]> · Thu, 17 Aug 2006 11:36:24 +0200

On Wednesday 16 August 2006 22:22, Mark Rivers wrote:
> Yes, there is a version of EPID which works with EPICS 3.14.x.
>
> It is included in the "std" module in synApps.
>
> http://www.aps.anl.gov/aod/bcda/synApps/std/std.html

Just stumbled over a documentation bug in 
http://www.aps.anl.gov/aod/bcda/synApps/std/epidRecord.html

Introduction says

>The major improvements in the EPID record compared to the PID record
> include: 
> [...]
> Changed the time units of the KI and KD terms from minutes to seconds

However, Section "Feedback Parameters" says

> Field Summary                                [...]
> KP    Proportional Gain                      [...]
> KI    Integral Gain, in repeats per minute   [...]
> KD    Derivative Gain, in repeats per minute [...]

which leaves me to wonder whether I would have to re-scale KI and KD 
when moving from pid to epid or not.

Another question with regard to replacing pid by epid: Apart from teh 
above scaling issue, have I understood it correct that if the following 
scenario:

a pid record controlling an ao record, the latter in OMSL=closed_loop, 
output OIF=incremental mode, DOL referencing pid's DM

would be replaced by

epid record having OUTL point to ao record's VAL, ao record in OIF=full 
and OMSL=supervisory mode?

then everything should work the same as before (modulo bugs/unwanted 
features)?

Ben
-- 
You've never looked into my eyes but don't you want to know
What the dark and the wild and the different know -- Melissa Etheridge

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System