[Dsg-htcc] [New Logentry] Re: LOLO gas pressure alarm for HTCC

[beng at jlab.org]

Logentry Text:
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The pressure changes in the HTCC were due to quick changes in the ambient pressure. Changing the input pressure to the MFC would have no effect as it is already above the minimum needed pressure for the flow rate.

Here's some suggestions …

- Change the LOLO setpoint and/or add a delay before alarming.

- After getting an alarm, verify that the flow is normal (if not also verify that the CO2 supply pressure is normal [on DC gas screen]).
- Check that the ambient pressure is the cause and not due to a leak, if it is a leak the detector pressure will not recover and won't track the ambient pressure.

- Increasing the CO2 flow will allow the pressure to recover faster at the expense of higher gas utilization. This won't completely prevent the spikes so is really just a last resort.

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This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3657045
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