Re: eiger2 vacuum sequencing power status

["Jemian, Peter R via Tech-talk" <tech-talk at aps.anl.gov>]

To avoid arcing high-voltage ion gauges in the intermediate vacuum region (of a double-crystal monochromator), I used a thermocouple vacuum gauge.  The gauge controller has setpoints for this range.  Each setpoint was connected to a relay contact.  The PLC (outside the vacuum chamber) sensed those contacts and operated a relay to energize when conditions allow.  Being the brutal sort, that relay switched on/off the mains power for the device being protected.

Pete


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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Keith Surrena via Tech-talk <tech-talk at aps.anl.gov>
Sent: Wednesday, February 11, 2026 2:38 PM
To: tech-talk at aps.anl.gov
Subject: eiger2 vacuum sequencing power status

We’re working on some PLC control for protecting our eiger2 4M that will live in vacuum and I’m looking for some feedback. Dectris specifies that it must be unpowered while chamber pressure is between 1bar and .01 mbar, so we’re interested in using an IoT relay to disable the power supply remotely. To verify that the detector is off, I was thinking about querying detector state with the State_RBV record. I noticed that so long as the read status rate is set reasonably, this should return “Error” as the state, instead of “Idle”. I could create logic based around these states but I’m worried that I could be missing a different interpretation of the “Error” state that could lead to believing the detector is unpowered when it isn’t. Are there any other records that would be useful for verification?


Keith Surrena
Research Support Specialist
Cornell High Energy Synchrotron Source