Experimental Physics and
Industrial Control System

"Ru Igarashi" <[email protected]> · Fri, 7 Aug 2009 18:55:50 -0600

One of the beamlines at the Canadian Light Source (CLS)
uses a Princeton Instruments (Roper) Quad-RO CCD detector
(2084x2084). We have used the synApps 'ccd' application
in the past, and have recently attempted to use the
'areaDetector' app instead.  In both cases, however,
when we run multiple image sequential scans, the hardware
locks up.  We essentially run a loop triggering the
detector via the ccd/areaDetector's acquire PV, wait
for a monitor from the acquire status, make sure the
status is "Done", do a few other tasks, then trigger
again.  There's at least 1.5 seconds between the end
of the trigger "Done" change-of-state and the subsequent
software trigger. The sequence is typically set for
2500-4000 exposures.

With 'ccd' we could get about 2500-3000 exposures before
the hardware locked up.  At least we think it is the
hardware because WinView still operates (e.g. close image,
start acquire, empty image frame appears, but no image),
restarting WinView does not solve the problem, and only
a hardware power cycle (long wait) solves the problem.
With 'ccd', there was a proxy app that displayed comm
traffic, and at the onset of the problem, it was clear
that communications were out of sync (command acks too
early, missing data packets) and remained out of sync.

We were hoping a switch to 'areaDetector' would resolve
this issue but it seems to have actually made the situation
worse: we now only get at most a few hundred exposures
before locking up.  Adding more time between exposures
(in case there was some sort of interference with
communication before or after an exposure) did not help,
either.

It looks as though areaDetector holds the status flag
"busy" until after the data is written to file, and we
don't think we see an overlap with disk or network activity
(haven't thought through caching issues properly), so it
doesn't seem to be a problem with triggering during the
previous image's file I/O.

The CCD hardware is linked to a Windows XP box via firewire.
XP is Service Pack 3 (so it isn't the old SP 2 bug). 
areaDetector is V1.4 (prebuilt), ccd was V1.6.  WinView
is V2.5.22.0.

Has anyone else experienced the same kind of problem
with their Roper CCD detector?  What can we do to either
further diagnose the problem or resolve it?  Perhaps
a Windows app that that can replace and perform the same
scan operations a few thousand times?

ru

-- 
Ru Igarashi                   Software & Instrumentation Specialist
e-mail: [email protected]  Canadian Light Source
ph: 306 657 3751              University of Saskatchewan
fax: 306 657 3535             Saskatoon SK S7N 0X4

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System