Experimental Physics and
Industrial Control System

"Oleg Makarov" <[email protected]> · Tue, 22 Jul 2008 11:50:20 -0500

Josh,
magnetic encoders with 0.25 micron resolution
(http://www.amo-gmbh.com/Dokumente/AMOSIN/Prospekt_LMI_e.pdf) are good
candidates for this task.

They are not absolute though, so they have to be used in combination with
homing procedure:

every time the system is powered on, a programmed motion across the
reference mark is needed.
Hope this helps,
Oleg Makarov
----- Original Message -----
From: "Josh Stein" <[email protected]>

To: <[email protected]>

Sent: Tuesday, July 22, 2008 9:34 AM

Subject: Revisiting a old problem - measuring the insertion device gap
Community,
We have been tasked with designing an interlock system involving the
measurement of our Insertion Devices here at the APS. Being a machine
protection system, it would be preferable to use an independent source of
measurement than is currently used by the control system. In the past it
has been an awkward problem coming up with accurate absolute measurements
of the gap due primarily to the fact that - by necessity - the area to be
measured is typically under a high radiation environment.
I'm trying to approach this problem from a fresh start - without any of
the existing baggage currently encumbering the control system.
So my question to everyone is simple to state, but I cannot come up with a
reasonable solution:
1) For each Insertion Device (ID) the system will need accurate (within a
few microns) and absolute measurement of the gap in two places (up and
down-stream).

2) The transducers need to be radiation "proof" - things like plastics,
teflon and electronics will not survive long enough (if at all) to be
viable
In a nutshell, that's really it.
I've investigated a few leads which seem promising, but would like to hear
fresh ideas from the experts (you guys).
Thanks in advance,
--Josh

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System