937B Controller Instruction Manual
pg. 43
Up to 3 MKS low power nude or Mini BA sensors can be degassed simultaneously.
The pressure must be below 1x10
-5
Torr in order for the degas cycle to begin. If degas is
attempted at a higher pressure, the Controller will display HIGH PRES for 10 seconds and will not
start degas.
6.6.2
Power (including degas) Control of a Sensor via 37 pin AIO D-sub
Connector
A connected pressure sensor can also be turned ON/OFF by sending a control signal to pins on the 37pin
D-sub connector located on the back of the AIO module as shown in Table 6-3.
To turn OFF a sensor, pull the appropriate pin per Table 6-3 to the ground. The sensor power is turned
OFF when the microprocessor detects a falling edge on the input pin. Cycling gauge channel power,
controller power or removing ground from the pin turns the gauge power back ON. Sensor power is
turned ON when a rising edge is detected.
Any of the three turn ON/OFF methods can be over-ridden by the other. For instance, front
panel ON/OFF can control a sensor last turned ON/OFF at the rear panel or via serial
commands
.
Since Hot Cathode modules operate a single sensor, pins 16, 18, 20 are used to control degas power.
Pin
Description
Pin
Description
1
Buffered Aout A1
11
Log/Lin Aout C1
2
Buffered Aout A2
12
Log/Lin Aout C2
3
Buffered Aout B1
13
Combination Aout 1
4
Buffered Aout B2
14
Combination Aout 2
5
Buffered Aout C1
15
Power A1
6
Buffered Aout C2
16
Power A2/Degas A1
7
Log/Lin Aout A1
17
Power B1
8
Log/Lin Aout A2
18
Power B2/Degas B1
9
Log/Lin Aout B1
19
Power C1
10
Log/Lin Aout B2
20
Power C2/Degas C1
21 to 37
Ground
Table 6-3 Pin Out for Analog Outputs and HC/CC Remote Control
Control pins 15-20 are pulled up by internal circuitry. No external voltage source is required
to pull up the pin.