Experimental Physics and
Industrial Control System

Tim Mooney <[email protected]> · Fri, 14 Jan 2011 02:26:10 -0600 (CST)

Damien,  You could do that, but there is software in the calc
module specifically for this kind of application.  userAve10.db
is (ten copies of) a sub-record based averaging database (much of
which I stole from Frank Lenkszus) that you can attach at run time to
any PV whose value you want to average.
The averaging algorithm can easily be triggered by a sscan record,
because it declares completion only after a user specified number of
samples have been averaged.  There is some (skimpy) documentation in
http://www.aps.anl.gov/bcda/synApps/calc/R2-8/calcDocs.html
The MEDM display is also intended to sort of show you how to use it.

To setup the averaging, set xxx:userAve1.INPB = "<your PV> CP"
(assuming <your PV> is periodically processed by some other entity).

For scanning, set the xxx:userAve1_mode to "ONE-SHOT", have the
sscan record write '1' to xxx:userAve1_acquire with a detector
trigger, and have it read the averaged value from xxx:userAve1.VAL.

Tim

----- Original Message -----
From: "Damien LYNCH" <[email protected]>
To: [email protected]
Sent: Thursday, January 13, 2011 7:00:44 PM
Subject: sscan and averaging [SEC=UNCLASSIFIED]

Hi, 

We have a sscan record setup to allow operators to scan over a sample in an ion source. Currently the data read at each scan position is whatever the detector is reading at that instant. We would like to acquire several times at each position and take the average. What is the best way of doing this? Should I set up a multidimensional scan and set the ACQM field in the inner sscan record to ACCUMULATE and perform the averaging elsewhere after the scan is finished? 

Thanks, 

Damien Lynch 

Accelerator IT Systems Engineer 

Institute of Environmental Research 

Australian Nuclear Science and Technology Organisation 

Locked Bag 2001 Kirrawee DC NSW 2232 

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-- 
Tim Mooney ([email protected]) (630)252-5417
Software Services Group (www.aps.anl.gov)
Advanced Photon Source, Argonne National Lab

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System