Experimental Physics and
Industrial Control System

"Leonard J. Reder" <[email protected]> · Thu, 01 Jun 2000 12:01:42 -0700

Hello:

I am utilizing the PID record within EPICS to perform closed loop
position control of some mirrors for our interferometer and some
questions came up.  The PID record's servo loop is now functioning
but not as expected.  Our application uses PZT like devices to position
a Newport Mirror mount and capacitive sensors to read back the position
into the CVL input of the PID record. The STPL input accepts the target
position for the mirror.  The PID record is feeding a AO record.
The AO is in incremental mode.

For this system integral gain term is all we expect would be needed but
the servo does not respond at all until some proportional gain term is
added independent of the value of the integral term.  Basically the
integral term seems to be ignored are we missing something?

One other problem I am seeing is that the medm/dm2k GUI does not seem
to be picking up the HOPR and LOPR field from the PID record.  Is this
a known bug.  How do I monitor on a GUI the ERR and DM fields?

We are using EPICS Release 3.13.0.beta12.

Any replies will be greatly appreciated.

Len

P.S. Thanks to Thomas Birke at Bessy and Kevin Tsubota at Keck for
     assistance in building the new dm2k application.

-- 
____________________________________________________
Leonard J. Reder
Jet Propulsion Laboratory
Interferometry Systems and Technology Section 383
Email: [email protected]
Phone (Voice): 818-354-3639
____________________________________________________

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System