Appendix A. ACIS Power Table

The following table lists the power consumed by ACIS due to its various components. This table was derived (stolen) from information gathered by Bob Goeke from the results of a series of Short Form and Long Form tests performed at Lincoln Laboratory (NOTE: This is taken from a note dated 19 May 1997, with some corrections from Ellen Sen on Sept. 9, 97). All the numbers shown include losses in the PSMC (order of 20% total):

Table 17. ACIS Power Table
State Side-A Side-B A or B Summary
PSMC Overhead 3w 3w   Total Overhead := 6w
BEP On and Running 14w 10w   Total BEP := 24w
2 FEPs On - - 16w  
3 FEPs + 3 FEPs On 25w 25w   Total FEP := 50w
All BEPs and FEPs On (idle) Total Static DPA := 74w
DEA 11th Board On 24w      
DEA 12th Board On   18w    
2 Video Boards On (idle)     7w  
6 Video Boards On (idle)     21w  
DEA 11th or 12th and 6 Video Boards On (idle) Total Static DEA := 45w
Additional power with 3 + 3 FEPs processing images 1w 1w    
Additional power with 6 Video Boards Clocking     8w  
Total Additional Power while clocking 6 CCDs Extra for clocks := 10w
Additional power of remaining 4 video boards are powered (idle)     15w  
Focal Plane Heater Operating at Nominal Cold (-120C)     2w/6w peak  
FP Heater Bakeout (30C)     52w peak  
Detector Housing Heater Operating at nominal cold case (-60C)     8w/72w peak


Detector Housing Heater Bakeout (25C)     72w peak  
Normal, clocking ACIS 145w
2 CCD Calibration 90w
Standby while maintaining thermal control 54w
Memory Save Mode (no thermal control) 20w
Bakeout slewing to temperature 168w
Bakeout at stable temperature (approx.) 128w
All ACIS On (not useful, but possible) 276w

The following table indicates the total current draw by ACIS, from the perspective of the service from the spacecraft:

Table 18. Total ACIS Current Draw
Voltage Current (nominal) Current (max)*
30VDC 4.8A 9.2A
22VDC 6.6A 12.5A
* Note that 10.8A is the maximum one could draw from one service, A or B

James E. Francis
Last modified: Wed Jan 12 16:46:44 EST