| CAID: MIPS-126 | Title: MIPS 70 um Voffset Adjustment Test | |
| System: MIPS | Principal: dmkelly | Deputy: kgordon |
| Objective: | Determine the optimum values for the MIPS 70um array offset DACs. |
| Description: | To maximize the dynamic range of the 70um
detector, we want to start the data ramps fairly
close to the lower rail of the A-D converter. At
the same time, we do not want to throw away
any
data because of a data ramp hitting the
bottom
rail of the A-D. 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.
Test Procedure:
Point at a region of sky that is not very bright
at 70um
Collect 5 3s DCEs in SUR mode for the
nominal
Voffset1=0xCA, Voffset2=0xC8
Patch Voffset to 0xC0 and 0xBE, wait 30s,
and
collect 5 3s
DCEs in SUR mode
Patch Voffset to 0xD4 and 0xD2, wait 30s,
and
collect 5 3s
DCEs in SUR mode
Patch back to the nominal values of
Voffset1=0xCA,
Voffset2=0xC8
|
| Day: 61.4847222222306 | Suggested Order: G100 | ||
| Must be preceded by these activities (list by CAID): MIPS-015 | |||
| Place in Schedule: This test should be done somewhat early in the Ge testing | |||
| Priority: Necessary | |||
Conditions | |||
| Maximum telescope temperature: | 12 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: 5 minutes
| | Real time downlink:
No | | |||
| Data Volume (uncompressed): 15 Mbits | |||
| List Blocks, AORs, SERs, IERs, or unique sequences required (uplink): special IER | |||
| List Analysis tools required (downlink): Any fits viewer (IRAF, Sirtfsee, IDL, pgperl, etc) | |||
| Estimate of data turn around: 4 hours | |||
| Description: Wait for data to reach the SSC; look at the starting points for the data ramps; determine the median and lowest starting values. Once completed, the optimum 70um Voffset DAC setting will be known and ground vs space differences will be characterized. | |||
| 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. | |||
Comments | |||
| References: | |||
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Additional Comments:
This test does not include a transfer function measurement and so has been renamed. | |||
| This activity last updated: 4/18/2002 1:59:58 PM | |||