Experimental Physics and
Industrial Control System

<[email protected]> · Thu, 21 Oct 2010 11:37:57 +0100

Hi,

We have done a similar thing at Diamond for our trim coil compensation.
We implemented a lookup table in a GenSub (in c). We have a number of
input parameters; the most significant one is Gap of course. We ended up
with a more complex table to support our helical undulators so that we
can compensate for the position of the phasing motion and whether we are
in circular or linear mode. 

Our acc-phys group do some analysis on the machine to establish the
compensation table. This table is then written to a waveform pv via a
simple client tool. We then use BURT to maintain the operation of the
table. There is also Auto Save and Restore that might be useful.
Personally I am not so keen on reading from the filesystem as it is more
difficult to have version control than the EPICs tools provide.

I can send you the code if you are interested but the base algorithms
are quite simple.

Regards,

Austen.

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Silver
Sent: 21 October 2010 09:41
To: tech-talk
Subject: Lookup table problem

hi, 

  I need to implement a function for insertion device like this:
  Read a two-dimensions table file from the disk, which is values for
gap positions and Correction coil power supplies (one gap value
corresponding to 4 power supply value). If a gap position is set from
the operator, four power supplies will be set automatically.
I want to use SNC language to do this, for reading the data from disk,
use an asub record for it. Is it ok? Is there any better ways? Did
anyone finish this job before? 
  Any suggestions are appreciated.

Best regards
Geyang  2010-10-21

-- 
This e-mail and any attachments may contain confidential, copyright and or privileged material, and are for the use of the intended addressee only. If you are not the intended addressee or an authorised recipient of the addressee please notify us of receipt by returning the e-mail and do not use, copy, retain, distribute or disclose the information in or attached to the e-mail.
Any opinions expressed within this e-mail are those of the individual and not necessarily of Diamond Light Source Ltd. 
Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachments are free from viruses and we cannot accept liability for any damage which you may sustain as a result of software viruses which may be transmitted in or with the message.
Diamond Light Source Limited (company no. 4375679). Registered in England and Wales with its registered office at Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System