Re: ADPilatus hangs after data collection completes

[Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>]

Hi Jesse,

A common reason for problems like this is clock synchronization.  ADPilatus looks at the timestamp on the file it is reading to make sure it is not "stale", since you might have reused the same file name as a previous collection.  If the time on the machine running ADPilatus is more than a few seconds different from the time on the file server then it can be waiting for a "new" file to appear.  Often the older Dectris machines do not start the ntp time server by default and the time can be way off.

Mark

---

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Jesse Hopkins via Tech-talk <tech-talk at aps.anl.gov>
Sent: Tuesday, February 17, 2026 10:32 AM
To: EPICS Tech-Talk <tech-talk at aps.anl.gov>
Subject: ADPilatus hangs after data collection completes

 

Hi folks,

Due to an issue with our newer Eiger2 detector I recently had to put an older Pilatus3 back into service at the beamline. It’s been a couple of years since we used it. I built a new IOC for it (as the previous IOC was quite old), using a version of AreaDetector and ADPilatus that was current as of May 2025. This is all running on EPICS base 7.0.9. Camserver version is 7.9.2.

I’m running into an issue where sometimes at the end of data collection the IOC hangs in a state where it thinks it is still collecting data. Camserver shows data collection is done. The images are in the expected data directory and that data directory is visible to the IOC. I think it’s an issue with the IOC not reading the images, as the image counter doesn’t seem to update during these exposures where it hangs. I’ve attached a screenshot that shows this issue (due to size limitations a second screenshot is not included that shows the same AD window along with a terminal window showing that the images exist in the expected location).

I should mention there are times when it finishes okay, but once it gets in this state of hanging at the end of data collection it seems to keep doing that until I restart the IOC (not tested too heavily).

I don’t see any obvious errors in the IOC. While it’s waiting for trigger it gets a timeout on what looks like a status query, and when I kill it the IOC reports an unexpected response:

2026/02/11 16:57:07.184 pilatusDetector:readCamserver, timeout=1.000000, status=1 received 0 bytes

2026/02/11 17:14:34.698 pilatusDetector:readCamserver unexpected response from camserver, no OK, response=13 ERR kill

Any thoughts on what might be going on here? I know that I could force the exposure to abort by setting the DelayTime shorter, but often we have 2-10 minutes between arming and actual triggering of the detector and so I want that to be sufficiently long that it wouldn’t abort in the middle of an exposure sequence if it didn’t see the images.

All the best.

- Jesse

 

----
Jesse Hopkins, PhD (he/him)
Director, BioCAT

Sector 18, Advanced Photon Source

Research Associate Professor, Illinois Tech