Observing Operations | Reviews | Survey Management

Instrument ID Switch Codes

Sloan Digital Sky Survey Technical Note
William N. Boroski
Last revised 10/01/99

Scope
This document defines the instrument ID switch encoding scheme used by the instrument change and interlock systems to detect and identify instruments on the SDSS 2.5-meter telescope.

Instrument ID Switches

Instruments installed on the instrument rotator will be identified by decoding a series of microswitches located near each of the three instrument kinematic mounts.  There will be one switch bank at each kinematic mount location;  each switch bank will contain four normally-closed (NC) microswitches.  NC switches are used in order to provide active-high signals to the interlock system.   Low signals from all switches on a given switch bank will indicate a disconnected cable.  High signals from all switches will indicate that the system is functioning but that no instrument is in place on the rotator.  A mismatch between the patterns from the three switch banks will indicate a fault condition, such as a broken wire or faulty switch in a given switch bank.

The following table lists the switch actuator output patterns for the instrument ID switches.  The actuators will be mounted on the instruments;  the switch banks will be mounted on the instrument rotator. 


 

Instrument ID Switch Codes
Mounted Device Instrument ID Switch Actuator Patterns
Instrument Switch Output Code
SB1
SB2
SB3
SB1     SB2     SB3
Disconnected Cable
none
none
none
0000    0000    0000
No Device
none
none
none
1111    1111    1111
Fiber Cartridge #1
0001
0001
0001
1110    1110    1110
Fiber Cartridge #2
0010
0010
0010
1101    1101    1101
Fiber Cartridge #3
0011
0011
0011
1100    1100    1100
Fiber Cartridge #4
0100
0100
0100
1011    1011    1011
Fiber Cartridge #5
0101
0101
0101
1010    1010    1010
Fiber Cartridge #6
0110
0110
0110
1001    1001    1001
Fiber Cartridge #7
0111
0111
0111
1000    1000    1000
Fiber Cartridge #8
1000
1000
1000
0111    0111    0111
Fiber Cartridge #9
1001
1001
1001
0110    0110    0110
Engineering Camera 
1010
1010
1010
0101    0101    0101
Unassigned
1011
1011
1011
0100    0100    0100
Unassigned
1100
1100
1100
0011    0011    0011
Unassigned
1101
1101
1101
0010    0010    0010
Imager CCD Camera
1110
1110
1110
0001    0001    0001


 
Submit comments and questions to the SDSS Helpdesk. Last updated 10/31/08