
946 Controller Instruction Manual
pg. 69
Pins 5, 6, and 7 are used for sensor identification. The cable needs to be matched to the type of hot
cathode so proper operating parameters like maximum degas power will be selected.
Table 7-1 shows the cable pinouts for Low Power Nude and Mini BA sensors.
Since high power is required to operate a Hot Cathode, especially, during degas, the maximum allowed
cable length is 50 ft (15 m), significantly shorter than for a cold cathode sensor.
937B Connector
End
Low Power
Nude (LPN)
A2
C
A3
G (Grid, 2x)
A4
F2
A5
FC (Fil. Comm.)
A6
F1
1--Jumpered to 2
2--Jumpered to 1
5--Jumpered to 6
6--Jumpered to 5
7--no connect
937B Connector End
Mini Ionization
Gauge (MIG)
A2
7
A3
2, 5
A4
4 (Fil. 2)
A5
3,6 (Fil.Comm.)
A6
1 (Fil. 1)
1--Jumpered to 2
2--Jumpered to 1
5
6--Jumpered to 7
7--Jumpered to 6
Table 7-1 Pin Assignments for HC Sensor (LPN on left, MIG on right)
If there is the possibility of forces on the cable, use a separate strain relief to prevent damage to the
sensor or controller. Cables are available in standard lengths of 10, 25 & 50 feet only. Tighten the cable
jackscrews into the mating screw locks to ensure proper electrical connection and prevent stress on the
connector.
Remove power from the controller before connecting or disconnecting the cable
from the sensor or controller.
7.3 Installing Convection Pirani, Convectron, or Pirani Sensors
7.3.1 Over Pressure Conditions
Danger of injury to personnel and damage to equipment exists on all vacuum
systems that incorporate gas sources or involve processes capable of pressuring the
system above the limits it can safely withstand.
For example, danger of explosion in a vacuum system exists during backfilling from
pressurized gas cylinders because many vacuum devices such as ionization gauge
tubes, glass windows, glass belljars, etc., are not designed to be pressurized.
Install suitable devices that will limit the pressure from external gas sources to the level
that the vacuum system can safely withstand. In addition, install suitable pressure relief