Keysight 34921A-34925A User’s Guide 21
Bank 2
34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
23L Interlock 221H 21L 22H 22L 23H
COM
2H
COM
2L
24H 24L 34H 34L 25H 25L 40H 40L
1234567891011121314151617
37LTSIL* 31H 31L 27H 27L 37H 33H 33L 29H 29L 39H 39L 35H 35L Interlock 2
18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
GND 26H 26L 36H 36L 32H 32L 28H 28L 38H 38L 30H 30L
AMP
43L
AMP
43I
AMP
44L
AMP
44I
50-Pin
D-Sub Male
Connector
*TSIL = Temperature
Sensor Interface Line.
Provides thermocouple
reference sensor serial
output line to the
mainframe processor.
Description Pin Description Pin Description Pin Description Pin Description Pin
21H 1 26H 35 31H 19 36H 37 COM2 H 7
21L 2 26L 36 31L 20 36L 38 COM2 L 8
22H 3 27H 21 32H 39 37H 23 Interlock 2 17
22L 4 27L 22 32L 40 37L 24 Interlock 2 33
23H 5 28H 41 33H 25 38H 43 GND 34
23L 6 28L 42 33L 26 38L 44 TSIL* 18
24H 9 29H 27 34H 11 39H 29 AMP 43L 47
24L 10 29L 28 34L 12 39L 30 AMP 43I 48
25H 13 30H 45 35H 31 40H 15 AMP 44L 49
25L 14 30L 46 35L 32 40L 16 AMP 44I 50
As a safety feature, interlock 2 pins (17 and 33) on Bank 2 must be shorted to
enable the Bank 2 Analog Bus relays to close. The optional 34921T terminal
block shorts these pins for you. This feature protects inadvertent routing of
high voltages from the Analog Bus to the D-sub connector of the module.