| CAID: MIPS-125 | Title: MIPS 24um Voffset Adjustment Test | |
| System: MIPS | Principal: dmkelly | Deputy: jmuzerolle |
| Objective: | Determination the optimum values for the MIPS 24um array offset DACs. |
| Description: | To maximize the dynamic range of the 24um
detector, we want to start the data ramps
close to
the lower rail of the A-D converter. At the same
time, to get accurate slopes, it is essential that
we not start the data ramps for any pixels at
lower than -32768 DN. In ground-based
testing, we
determined optimal DAC settings for the offset
voltage DACs to meet these criteria. In this
test, we will confirm those settings.
Procedure:
Point at the sky. The sky level is unimportant.
Collect 5 3s DCEs in RAW mode for the
nominal
24um Voffset of 0x6b
Patch Voffset to 0x6a, wait 15s, and collect 5
3s DCEs in RAW mode
Patch Voffset to 0x69, wait 15s, and collect 5
3s DCEs in RAW mode
Patch Voffset to 0x68, wait 15s, and collect 5
3s DCEs in RAW mode
Patch Voffset to 0x6c, wait 15s, and collect 5
3s DCEs in RAW mode
Patch Voffset to 0x6d, wait 15s, and collect 5
3s DCEs in RAW mode
Patch Voffset back to its nominal value of
0x6b
|
| Day: 61.3381944444482 | Suggested Order: D100 | ||
| Must be preceded by these activities (list by CAID): MIPS-015 | |||
| Place in Schedule: Very early in the 24um testing. If the offsets are set improperly, we will not get valid SUR data for our other tests. This test must come sometime after a 24um thermal anneal, but not in the first 20 minutes after an anneal. | |||
| Priority: Necessary | |||
Conditions | |||
| Maximum telescope temperature: | 40 K | ||
| Minimum telescope temperature: | 5.5 K | ||
| Should activity be repeated if focus changes? | No Repeat if focus changes by 0 mm | ||
| Maximum absolute pointing uncertainty: | 3600 arcsec (1 sigma radial) | ||
| Maximum precision offset uncertainty: | 3600 arcsec (1 sigma radial) | ||
| Observatory configuration: | standard | ||
| Go/No Go criteria: | CE aliveness must be established and state transitions must be verified | ||
Duration: 10 minutes
| | Real time downlink:
No | | |||
| Data Volume (uncompressed): 28 Mbits | |||
| List Blocks, AORs, SERs, IERs, or unique sequences required (uplink): Special IER | |||
| List Analysis tools required (downlink): Fits viewer (IRAF, Sirtfsee, IDL, pgperl, etc) | |||
| Estimate of data turn around: 4 hours | |||
| Description: Optimum DC offset level for the 24um array will be known. Ground vs in-orbit differences will be determined. | |||
| Can proceed in parallel with other activity: Yes | |||
| Must outcome be confirmed before next activity: No | |||
| Method of Confirmation: Data analysis and comparison to ground-based measurements. | |||
| Success criteria: The ramp starting points need to be reasonable and repeatable so that we can choose optimum settings for use during the mission. | |||
| Contingency plan: If the Voffset values are not stable or if they have changed a lot since ground testing, some careful analysis will be required to determine whether the MIPS instrument is healthy. If the Voffset values cannot be changed, we will have to determine if there is a fault in the electronics or commanding. | |||
Comments | |||
| References: | |||
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Additional Comments:
This is not a transfer function measurement, so the test title should be updated, as indicated above. | |||
| This activity last updated: 4/18/2002 1:59:11 PM | |||