TetrAMM triggering

[prjemian]

• add support for Caen picoammeter - TetraAMM #878

As a beam-position monitor, the TetrAMM should be operated in continuous mode. The trigger mode should make sure the detector ACQUIRE button is pressed and then set its status object to DONE. This will allow a subsequent .read() to return the current values.

The default .stage_sigs sets acquire to Done and the mode to Single. Change this to do none of these: .stage_sigs = {}

We found this today while running bp.rel_scan([tetramm] ...) at XPCS. The scans were getting stuck because the tetramm trigger status object never finished.

[prjemian]

Watch the XPCS repo for this incoming change.

[qzhang234]

This is the scan that was stuck (first image). On second image, between scan point 15 and 16, the time gap is nearly 2 minute

[prjemian]

Two commits on this:

• aps-8id-dys/bluesky@a2bf7e8
• aps-8id-dys/bluesky@0ae10c6