[INSTRM-342] CCD temperature readings are nuts, Created: 30/Apr/18 Updated: 13/Jul/18 Resolved: 13/Jul/18 |
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| Status: | Won't Fix |
| 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: | Won't Fix | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Description |
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The readings from the CCDs went bad during the cool down. For both, the warmest good reading was 144.38. Below that all readings have been crazy: 2018-04-30 07:35:12.180Z cmds 20 Actor.py:491 new cmd: temps status 2018-04-30 07:35:12.181Z root 10 feeControl.py:798 sending command :'~rt,FEE\n': 2018-04-30 07:35:12.184Z root 10 feeControl.py:856 received :~rt,FEE: 2018-04-30 07:35:12.242Z root 10 feeControl.py:856 received :291.50: 2018-04-30 07:35:12.242Z root 10 feeControl.py:798 sending command :'~rt,PA\n': 2018-04-30 07:35:12.246Z root 10 feeControl.py:856 received :~rt,PA: 2018-04-30 07:35:12.447Z root 10 feeControl.py:856 received :270.63: 2018-04-30 07:35:12.447Z root 10 feeControl.py:798 sending command :'~rt,ccd0\n': 2018-04-30 07:35:12.451Z root 10 feeControl.py:856 received :~rt,ccd0: 2018-04-30 07:35:13.119Z root 10 feeControl.py:856 received :19199440.48: 2018-04-30 07:35:13.119Z root 10 feeControl.py:798 sending command :'~rt,ccd1\n': 2018-04-30 07:35:13.123Z root 10 feeControl.py:856 received :~rt,ccd1: 2018-04-30 07:35:13.790Z root 10 feeControl.py:856 received :18203293.12: 2018-04-30 07:35:13.791Z cmds 20 CommandLink.py:121 > 1 21590 i ccdTemps=270.63,19199440.48,18203293.12 2018-04-30 07:35:13.791Z cmds 20 CommandLink.py:121 > 1 21590 : I feel that we have seen this before and that it was fixed (it must have been). But cannot find ticket/email. |
| Comments |
| Comment by cloomis [ 01/May/18 ] |
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We saw this before and did not fix it because 145K is 30K below operational temperatures, and there are other sensors near the CCD without this problem. |
| Comment by shope [ 01/May/18 ] |
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Measurements were below the physical measurement limits imposed by the hardware. All measurements are returned in Kelvin which means they cannot be negative. Firmware was modified to return -1.0 for measurements below the normal operating range. |
| Comment by cloomis [ 13/Jul/18 ] |
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See comments: This will not be an issue during operation, we do have other – not clipped – temperature sensors on the FPA, and the firmware now reports a sensibly invalid reading. |