The MSFC-SPEC-2058 Software As-Built spec has the limits on the 
Auto Mode control software as 

Primary Heater Upper limit 		30C
Secondary Heater Upper limit 	32C
Both Heaters on Upper limit 	32C

Lower limit in all modes 		21C 

I'm waiting on a call back from  Louis Simmeone who has the actual 
software verification/validation results with the actual performance 
numbers. If I'm remembering correctly the values were within a 1/2 degree. 

Below is the info that I sent to Roger and Hugh this morning. 

DeLisa
------------------------------------------------------------------------------
DeLisa Wilkerson/ED13
Digital Systems Design Team
Marshall Space Flight Center
MSFC, AL 35812
256.544.4967v, 256.544.9582f
delisa.wilkerson@msfc.nasa.gov
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From: 	Wilkerson, Delisa
Sent: 	Thursday, August 26, 1999 9:04 AM
To: 	Christian, Hugh
Cc: 	Chassay, Roger; Trice, David
Subject: 	FW: LIS HEATER AUTO CONFIG

Hugh,

This sounds like a bit flip occurred in the upper bits of the primary heater 
housekeeping data. This could have occurred at the housekeeping A/D, the 
processor data memory, or on a register internal to the processor. The control 
algorithm does not detect or correct for bit flips (i.e. it does not perform 
double check or any other verification/correction method) before switching 
heaters.  Also, the read rate for the housekeeping data exceeds that of the 
packet transmission so the data that caused the heater change was most likely 
overwritten.  

If the heaters have been performing well and the optics temperatures are being 
monitored by the ground, the software "Heater Auto Select " can be disabled 
through command. Of course after a reset it will power-up to 
"Heater Auto Select Mode 1" , where it is checking the upper limits only,  
and the primary heater will be enabled. 

DeLisa Wilkerson/ED13
Digital Systems Design Team
Marshall Space Flight Center
MSFC, AL 35812
256.544.4967v, 256.544.9582f
delisa.wilkerson@msfc.nasa.gov