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GALILEO

The Galileo Energetic Particles Detector

 

Galileo EPD Handbook

 

Chapter 1. Instrument Summary

 

Galileo EPD Housekeeping Functions (continued)

Source: R. C. Moore, August 26, 1979

 

Table 2. Galileo EPD Subcommutated Housekeeping

 

Documents marked with * are not available on this website; reference APL S3 Division archives.

 

Cursor Value Function Conversion Rule Comments
1 Motor housing temperature (originally analog) (See Engineering Unit Conversion Function for Temperatures in *S3D-70-000.) High and low alarm thresholds are in functions with cursor values 55 and 56.
2 Motor telemetry byte #1 Bit 1 - Scan error
   0 ® no error
   1 ® error
(A detailed description of the motor telemetry is found in *EPD-085-79.)
Scan error indicates that more pulses were delivered to the motor to make a sector change than should have been necessary.
Bit 2 - Fast scan abort flag
  0 ® normal
  1 ® 
abort
Fast scan abort indicates that the fast scan mode was automatically aborted due to excessive depth of discharge of motor capacitor bank. Returns to normal scan.
Bit 3 - Emergency count flag
  0 ® normal
  1 ® emergency count number, modulo 32, occupies bits 4-8 instead of motor position data
In the emergency mode, whenever the motor is between sectors, this bit goes to logic 1. Emergency count number is the number of 1.8° steps attempted since the motor was last on sector centerline.
Bit 4 - Direction indicator
  0 ® counterclockwise
  1 ® clockwise
Clockwise means sector numbers are increasing.
Bit 5 - Centerline indicator
  0 ® off center
  1 ® on center
Marks center (±1.3°) of sector.
Bits 6-8 - Motor position code
  P = 4B6 + 2B7 + B
8
P is the sector number.
3 Motor telemetry byte #2 Bit 1 - Emergency mode indicator
  0 ® normal
  1 ® emergency
In emergency mode, motor moves one step per trigger instead of one sector per trigger.
Bit 2 - Open loop mode indicator
  0 ® closed loop
  1 ® open loop
In closed loop mode, the motor moves until the next centerline is found or an automatic cease scan occurs. In open loop mode, a fixed number of steps is applied to the motor, to change sectors.
Bit 3  
Modified scan (closed loop mode)
  0 ® normal scan using end sectors 0 and 7
  1 ® Modified scan using end sectors programmed by ground command
Limited scan (open loop mode)
  0 ® normal scan
  1 ® limited scan
 
For detailed descriptions of normal scan and limited scan, see *EPD-085-79.
Bit 4 - Fast scan
  0 ® normal scan
  1 ® fast scan
Fast scan: motor receives triggers every two logical records (every 2-2/3 seconds).
Bit 5 
Go to sector N (closed loop mode)
  0 ® normal
  1 ® go to sector N and stay there
Respond to N triggers (open loop mode)
  0 ® normal
  1 ® stop scanning after N triggers
Value of N is found in bits 6, 7, and 8.
Bits 6-8 - "N"
N = 4B6 + 2B7 + B
8
 
4 Motor telemetry byte #3 Bit 1 - Alternate step rate mode
  0 ® normal
  1 ® alternate step rate
Normal: ~50 steps/sec (~90°/sec)
Alternate: ~60 steps/sec (108°/sec)
Bits 2-4 - CCW end-sector
  Sccw = 4B2 + 2B3 + B
4
Bits 2-4 are not used in open loop mode.
Bit 5 - Chicken Mode (closed loop mode)
  0 ® normal
  1 ® chicken mode
"Chicken Mode" is a mode in which most of the time is spent behind the shield (sector 0). (Not used in open loop mode.)
Bits 6-8 - CW end-sector
  Scw = 4B6 + 2B7 + B
8
Bits 6-8 are not used in open loop mode.
5 Autocalibrator index #1 I1 = 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8
B1 is ignored.
This index identifies contents of next subcommutated function, according toTable 1 and *EPD-050-79.
6 Autocalibrator AGC voltage #1 (originally analog) AGC1 = 2.56B1 + 1.28B2 + .64B3 + .32B4 + .16B5 + .08B6 + .04B7 + .02B8 0 volts £ AGC £ 5.1 volts
7 Motor telemetry byte #4 N = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 N = number of invalid motor commands, modulo 256.
8 Motor telemetry byte #5 Bits 1 & 2 not used.
Bits 3-7 - step count (closed loop mode)
  SC = 16B3 + 8B4 + 4B5 + 2B6 + B7
Bits 3-7 not used in open loop mode.
Step count is the number of steps required to make the most recent sector change.
Bit 8 - cease scan flag (closed loop mode)
  0 ® normal
  1 ® cease scan
Bit 8 not used in open loop mode.
"Cease scan" indicates that the motor was unable to find a centerline during a closed loop sector change attempt. Motor automatically tries to return to centerline of previous sector.
9 LEMMS telescope temperature (originally analog) (See Engineering Unit Conversion Function for Temperatures in *S3D-79-000.) High and low alarm thresholds are in functions with cursor values 61 and 62.
10 Number of invalid bus commands, modulo 256 NIC = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 NIC is the sum of invalid data system commands and invalid scanning system commands. Function at cursor 7 is scanning system invalid command count.
11 Autocalibrator index #2 (Same as for cursor #5) See *EPD-050-79.
12 Autocalibrator AGC voltage #2 (originally analog) (Same as for AGC1 - see cursor #6.)  
13 Memory dump cursor (8 MSBs) MDC = 32768B1 + 16384B2 + 8192B3 + 4096B4 + 2048B5 + 1024B6 + 512B7 + 256B8 + (least significant half) Least significant half of MDC is in channels 9 and 95 of the EPD logical record (see *S3D-79-093).
14 Motor dwell period MDP = 170.67B1 + 85.33B2 + 42.67B3 + 21.33B4 + 10.67B5 + 5.33B6 + 2.67B7 + 1.33B8 MDP is programmable by ground command in integer multiples of 1.333 seconds. During accelerated scan, MDP = 2.667. Default (initial) value for MDP is 20 seconds.
15 CMS telescope temperature (originally analog) (See Engineering Unit Conversion Function for Temperatures in *S3D-79-000.) High and low alarm thresholds are in functions with cursor values 67 and 68.
16 Supervisory data parity error count SDP = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 SDP is the number of parity errors detected by EPD bus adapter since last power-on, modulo 256.
17 Autocalibrator index #3 (Same as for cursor #5) See *EPD-050-79.
18 Autocalibrator AGC voltage #3 (originally analog) (Same as for AGC1 - see cursor #6.)  
19 Upper memory checksum limit (8 MSBs) UMCL = 32768B1 + 16384B2 + 8192B3+ 4096B4 + 2048B5 + 1024B6 + 512B7 + 256B8 + (least significant half) Least significant half of UMCL is in function with cursor value = 20.
20 Upper memory checksum limit (8 LSBs) UMCL = 128B1 + 64B2 + 32B3 + 16B4+ 8B5 + 4B6 + 2B7 + B8 + (most significant half) Most significant half of UMCL is in function with cursor value = 20.
21 Main electronics temperature (originally analog) (See Engineering Unit Conversion Function for Temperatures in *S3D-79-000.) High and low alarm thresholds are in functions with cursor values 73 and 74.
22 Memory checksum MCM = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8  
23 Autocalibrator index #4 (Same as for cursor #5) See *EPD - 050-79.
24 Autocalibrator AGC voltage #4 (originally analog) (Same as for AGC1 - see cursor #6.)  
25 Lower memory checksum limit (8 MSBs) LMCL = 32768B1 + 16384B2 + 8192B3+ 4096B4 + 2048B5 + 1024B6 + 512B7 + 256B8 + (least significant half) Least significant half of LMCL is in function with cursor value = 26.
26 Lower memory checksum limit (8 LSBs) LMCL = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 + (most significant half) Most significant half of LMCL is in function with cursor value = 25.
27 EPD input current (originally analog) (See Engineering Unit Conversion Function for Current in *S3D-79-000.) High and low alarm thresholds are in functions with cursor values 49 and 50.
28 EPD data parity error count EDP = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 EDP is the number of parity errors detected by EPD bus adapter during EPD bus transactions since last power-on, modulo 256.
29 Autocalibrator index #5 (Same as for cursor #5) See *EPD-050-79.
30 Autocalibrator AGC voltage #5 (originally analog) (Same as for AGC1 - see cursor #6.)  
31 LEMMS PHA A K1 AK1 = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 0 £ A K1 £ 192
32 LEMMS PHA A K2 AK2 = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 0 £ A K2 £ 2
33 +60 volts bias (originally analog) (See Engineering Unit Conversion Function in *S3D-79-000.)  
34 Power switch status byte #1 Bit n = 0 ® LEMMS AMP (9-n) off
Bit n = 1 ® LEMMS AMP (9-n) on
1  £  £ 8
(See *S3D-79-104.)
35 Autocalibrator index #6 (Same as for cursor #5) See *EPD-050-79.
36 Autocalibrator AGC voltage #6 (originally analog) (Same as for AGC1 - see cursor #6.)  
37 LEMMS PHA E K1 EK1 = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 0 £ E K1 £ 192
38 LEMMS PHA E K2 EK2 = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 0 £ E K2 £ 2
39 +20 volts bias (originally analog) (See Engineering Unit Conversion Function in *S3D-79-000.)  
40 Power switch status byte #2 B1 - spare
B2 = 1 ® calibrator on
B2 = 0 ® calibrator off
B3 = 1 ® PHA on
B3 = 0 ® PHA off
B4 = 0 
® TOF on
B4 = 0 ® TOF off
B5 = 1 ®
 CMS electronics on
B5 = 0 ® CMS electronics offCMS electronics off
B6 = 1 ® Detector bias high
B6 = 0 ® Detector bias normalDetector bias normal
B7 = 1 ® CMS J' bias on (+20V)
B7 = 0 ® CMS J' bias offCMS J' bias off
B8 = 1 ® LEMMS A detector bias on (+60V)
B8 = 0
 ® LEMMS A detector bias off
(See *S3D-79-104.)
41 Autocalibrator index #7 (Same as for cursor #5) See *EPD-050-79.
42 Autocalibrator AGC voltage #7 (originally analog) (Same as for AGC1 - see cursor #6.)  
43 LEMMS PHA F K1 FK1 = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 0 £ F K1 £ 192
44 LEMMS PHA F K2 FK2 = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 0 £ F K2 £ 2
45 -15 Volts power (originally analog) (See Engineering Unit Conversion Function in *S3D-79-000.)  
46 Power switch status byte #3 B1 = 1 ® LEMMS -10V power on
B1 = 0 ® LEMMS -10V power off
B2 = 1 ® motor on
B2 = 0 ® motor off
B3 = 1 ® motor RAM exchanged 
B3 = 0 ® motor RAM normal
B4 B5 B6 - spares
B7 = 1 ®
 LEMMS E11LEMMS E11 thresh. high
B7 = 0 ® LEMMS E11 thresh. normal
B8 = 1 ® LEMMS A1 thresh. high
B8 = 0 
® LEMMS A1 thresh. normal
 
47 Autocalibrator index #8 (Same as for cursor #5) See *EPD-050-79.
48 Autocalibrator AGC voltage #8 (originally analog) (Same as for AGC1 - see cursor #6.)  
49 Upper alarm threshold for EPD input current UTIC = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 Engineering unit conversion is in *S3D-79-000.
50 Lower alarm threshold for EPD input current LTIC = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 See comment at cursor 49.
51 +10 Volts power (originally analog) (See Engineering Unit Conversion Function in *S3D-79-000.)  
52 Power switch status byte #4 B1 = 1 ® TOF logical condition off
B1 = 0 ® TOF logical condition on
B2 - spare
B3 = 1 ® CMS analog J'K' on
B3 = 0 ® CMS analog J'K' off
B4 = 
1 ® CMS analog L on
B4 = 0 ® CMS analog L off
B5 = 
1 ® CMS analog Jc on
B5 = 
0 ® CMS analog Jc off
B6 = 
1 ® CMS analog Jb on
B6 = 
0 ® CMS analog Jb off
B7 = 1 ®
 CMS analog Ja on
B7 = 0 ® CMS analog Ja off
B8 = 1 ® CMS prime select on
B8 = 0 ®
 CMS prime select off
 
53 Autocalibrator index #9 (Same as for cursor #5) See *EPD-050-79.
54 Autocalibrator AGC voltage #9 (originally analog) (Same as for AGC1 - see cursor #6.)  
55 Upper alarm threshold for motor temperature UTMT = 128B1 + 64B2 + 32B3 + 16B4+ 8B5 + 4B6 + 2B7 + B8 See comment at cursor #49.
56 Lower alarm threshold for motor temperature LTMT = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 See comment at cursor #49.
57 +6 Volts power (originally analog) (See Engineering Unit Conversion Function in *S3D-79-000.)  
58 PHA control byte B1 = EP1        priority = 2 EP1 + EP0
B2 = EP0          "                 "        "
B3 = 0 ® priority override
B3 = 1 ® priority normal
B4 = 
1 ® PHA reset
B4 = 0 ® PHA normal 
B5 = LS1      LEMMS select = 2 LS1 + LS0
B6 = LS0         "                       "        "
B7 = 0 ®
 P read active
B7 = 1 ® P read inactive
B8 = 0 ® LEMMS mode
B8 = 1 ® CMS mode
 
59 Autocalibrator index #10 (Same as for cursor #5) See *EPD-050-79.
60 Autocalibrator AGC voltage #10 (originally analog) (Same as for AGC1 - see cursor #6.)  
61 Upper alarm threshold for LEMMS telescope temperature UTLT = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 See comment at cursor #49.
62 Lower alarm threshold for LEMMS telescope temperature LTLT = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 See comment at cursor #49.
63 +3 Volts power (originally analog) (See Engineering Unit Conversion Function in *S3D-79-000.)  
64 (spare)    
65 Autocalibrator index #11 (Same as for cursor #5) See *EPD-050-79.
66 Autocalibrator AGC voltage #11 (originally analog) (Same as for AGC1 - see cursor #6.)  
67 Upper alarm threshold for CMS telescope temperature UTCT = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 See comment at cursor #49.
68 Lower alarm threshold for CMS telescope temperature LTCT = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 See comment at cursor #49.
69 -3 Volts power (originally analog) (See Engineering Unit Conversion Function in *S3D-79-000.)  
70 (spare)    
71 Autocalibrator index #12 (Same as for cursor #5) See *EPD-050-79.
72 Autocalibrator AGC voltage #12 (originally analog) (Same as for AGC1 - see cursor #6.)  
73 Upper alarm threshold for main electronics temperature UTET = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 See comment at cursor #49.
74 Lower alarm threshold for main electronics temperature LTET = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8 See comment at cursor #49.
75 -6 Volts power (originally analog) (See Engineering Unit Conversion Function in S*3D-79-000.)  
76 (spare)    
77 Autocalibrator index #13 (Same as for cursor #5) See *EPD-050-79.
78 Autocalibrator AGC voltage #13 (originally analog) (Same as for AGC1 - see cursor #6.)  
79 Upper alarm threshold #6  
80 Lower alarm threshold #6  
81 -10 Volts power (originally analog) (See Engineering Unit Conversion Function in *S3D-79-000.)  
82 (spare)    
83 Autocalibrator index #14 (Same as for cursor #5) See *EPD-050-79.
84 Autocalibrator AGC voltage #13 (originally analog) (Same as for AGC1 - see cursor #6.)  
85 (spare)    
86 (spare)    
87 Dust cover deployment (originally analog) DC = 128B1 + 64B2 + 32B3 + 16B4 + 8B5 + 4B6 + 2B7 + B8    0 £ DC £ 32 ® covers closed.

  33 £ DC £ 96 ® sector 1 cover open, sector 7 cover closed.

  97 £ DC £ 137 ® sector 1 cover closed, sector 7 cover open.

  138 £ DC £ 255 ®
 both covers open.
88 (spare)    
89 (spare)    
90 (spare)    
91 (spare)      

 

 

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Updated 8/23/19, Cameron Crane

QUICK FACTS

Manufacturer: The Galileo Spacecraft was manufactured by the Jet Propulsion Laboratory, Messerschmitt-Bölkow-Blohm, General Electric, and the Hughes Aircraft Company.

Mission Duration: Galileo was planned to have a mission duration of around 8 years, but was kept in operation for 13 years, 11 months, and 3 days, until it was destroyed in a controlled impact with Jupiter on September 21, 2003.

Destination: Galileo's destination was Jupiter and its moons, which it orbitted for 7 years, 9 months, and 13 days.