[INSTRM-1526] Implement internal FEE routine for LBNL wipe Created: 23/Feb/22  Updated: 28/Apr/22  Resolved: 28/Apr/22

Status: Done
Project: Instrument control development
Component/s: ics_xcu_fee
Affects Version/s: None
Fix Version/s: None

Type: Task Priority: Normal
Reporter: cloomis Assignee: shope
Resolution: Done Votes: 0
Labels: SPS
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Relates
relates to INSTRM-1556 Call new internal FEE routine for era... Done
relates to INSTRM-7 CCD flats show regions of vertical st... Done
Reviewers: cloomis

 Description   

[ I thought I had filed this earlier but apparently not. ]

The LBNL wipe routine is believed to ameliorate the tearing seen in INSTRM-7. We have a been using an external loop which is slow. Implement an internal routine instead. Specifically:

  • Push parallels up to some newly specified voltage
  • Ramp Vbb down to zero volts at a specified rate
  • Dwell for 0.5 seconds
  • Ramp Vbb back up to its original voltage at the same rate
  • When Vbb reaches a defined threshold, drop the parallels to their original value
  • Continue ramping Vbb

So command like:

~SEQ,[ramp_time_ms],[threshold],[parallel voltage]

 Comments   
Comment by cloomis [ 23/Feb/22 ]

Implemented in Firmware Rev: 220211-01

Adds the following command:

rSeq,[new parallel voltage],[Vthreshold to revert Parallels],[number of ~5ms steps to ramp Vbb],[Vbb dwell time in ms at 0V]\n

Example:

rSeq,8,8,100,1000\n
rSeq: Run Sequence
8: Set Parallels to 8V (this is an ascii float value)
8: Set the Vbb positive Ramp threshold for reverting parallels to 8V (this is an ascii float)
100: Set the number of ramp steps to 100, which approximates to 500ms (this is an ascii int)
1000: Set the Dwell time to 1000, which approximates to 1000ms (this is an ascii int)
\n: Execute the command.

Comment by cloomis [ 23/Feb/22 ]

And it turns out that all of this might have been unnecessary. The VBB circuit had a diode which was blocking some part of the charging, and so VBB was taking a very long time to drop to 0V. So it may well be that the only thing I was doing was inserting a very long time while VBB was going from 30V to 0V. In any case we have a new knob.

Comment by cloomis [ 23/Feb/22 ]

Needs burning and testing.

Comment by cloomis [ 28/Apr/22 ]

We are calling this and it evidently works.

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