Instruction Manual WGM701 Wasp
InstruTech
Page 13
4
Setup and Operation
4.1
Gauge start up and operation
Read this user manual in its entirety before operating the instrument.
The signal output is available when power is applied to the gauge. Allow for a stabilizing time of approx. 10 min.
Once the gauge has been switched on, it can remain in operation continuously regardless of the pressure.
Connect power to the WGM701 using the designated pins 4 and 2 of the 9-pin D-sub connector.
Alternatively,
you can power the device by connecting InstruTech’s PS501
-A power supply to the connector.
The gauge consists of two separate measuring systems (Pirani and cold cathode system based on the inverted
magnetron principle). The two sensors are designed to operate as one combined measuring unit. The optimum
measuring configuration for the particular pressure range, in which measurement is performed, is shown below:
7.6 x 10
-4
Torr 760 Torr
7.6 x 10
-10
Torr 7.6 x 10
-3
Torr
4.2
Cold Cathode sensor activation delay
An ignition delay occurs when cold cathode gauges are switched on. The delay time increases at low pressures
and is typically:
7.60 ×10
-6
…
7.60 × 10
-3
Torr < 1 second
7.6 × 10
-8
…
7.6 × 10
-6
Torr
< 20 seconds
3.75 × 10
-9
…
7.6 × 10
-8
Torr < 2 minutes
< 3.75 × 10
-9
Torr
< 20 minutes
As long as the cold cathode measuring circuit has not ignited, the output signal is provided by the Pirani
measuring circuit.
If the cold cathode is activated at a pressure less than 2.25 × 10
-10
Torr, the gauge cannot recognize whether the
cold cathode sensor has ignited.
Once flanged on, permanently leave the gauge in the operating mode irrespective of the pressure.
