MKS HPS 947 Series, Руководство по эксплуатации и обслуживанию, Страница: 31 / 40

25
HPS
®
Products Series 947 CEP System
Cleaning the CEP Sensor
Roughing pump oils and other fluids condensing or decomposing on the
heated filament can contaminate the Sensor. This changes the emissivity of
the filament, which in turn can cause the calibration to change, especially at
low pressure.
It is not advisable to clean the Sensor. Trying to clean it
may either deform or break the filament, and the deformed
filament would then cause additional error from a shift in
the Sensor's output.
Replace the Sensor if it becomes contaminated (see Accessories, p. 26).
Testing the CEP Sensor
Make sure the Controller is turned off and the Sensor is disconnected from
the cable beforehand.
1. With a #1 Phillips head screwdriver, remove the two
screws to separate the connector/electronics
subassembly from the end of the Sensor as
shown to the right.
2. Check the resistance on the Sensor's PC
board for the pins listed in the first column
below. Test the Sensor with an ohmmeter
with less than 5 mA of current. The
resistance readings of a normal Sensor
measured at atmospheric pressure and at
room temperature (20°C) are listed in the
middle column. If the condition shown in the
right column exists, the Sensor should
be replaced.
Sensor PC board
Check Resistance (W) If Reading Is
20
20 x 10
6
27
20 x 10
6
Higher, filament is broken or
burned out.
Lower, Sensor is damaged or
contaminated.
Higher, temperature compensation
winding is broken.
Lower, temperature compensation
winding is shorted to Sensor body.
F1 to F2
F1 to Sensor port
F2 to Sensor port
TC1 to TC2
TC1 to Sensor port
TC2 to Sensor port
TC1
TC2
F1
F2
Sensor side view