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Message ID: 2486
Entry time: Wed Dec 4 17:09:44 2019
In reply to: 2349
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Author: |
anchal |
Type: |
DailyProgress |
Category: |
TempCtrl |
Subject: |
Increased range of out-of-loop temperature sensor |
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This has happened few times now that acromag channel for the can heater driver stopped updating according to the PID script and the can gets heated to a very high temperature. This pushes the temperature out of the ranges of the current AD590 temperature sensor board. I have changed the range of channel 2 (this was being used for out-of-loop) to ensure we can still see some meaningful temperature value when such incidents happen. I have replaced R18 from 100k to 27k. The updated table is:
CH No on Board |
EPICS Channel Name |
Temperature Conversion Function (ºC) |
Range (ºC) |
1 |
C3:PSL-TEMP_TABLE |
= V/0.810875 + 27.30248869 |
13.860-40.745 |
2 |
C3:PSL-TEMP_VACCAN_OOL |
= V/0.43875 + 33.3115385 |
8.450-58.155 |
3 |
C3:PSL-TEMP_VACCAN_INLOOP |
= V/1.625 + 33.3115385 |
26.604-40.020 |
Weird phenomenon?
- I'm not sure this problem occurs though. Right now the out-of-loop temperature sensor shows that the temperature of the can is 55 Degree Celsius.
- This is also not cooling down fast. Last time it took days for it to cool down to set value.
- The alignment of the cavities change vertically when the can temperature is significantly different from the set value of 34.38 Degree Celcius.
- This hinders them from locking properly unless I tune the alignment back. But when the can will cool down finally, they will be misaligned again.
- Also, I just refuse to believe it is actually that hot, but I check the voltage after the transimpedance amplifier in temperature sensor boards and two independent AD590s are reporting this.
- And anyways, why is the acromag output channel getting frozen anyways.
- That being said, this is an irreproducible but non-harmful problem yet, so lower priority than the FSS saga going on.
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