FPG8601™/VLPC™ OPERATION AND MAINTENANCE MANUAL
© 2007 DH Instruments, a Fluke Company
Page 124
Use the
<Diagnostics Display>
in FPG Tools to monitor the output of the sensor.
Allow the vacuum pump to pull down the sensor so that a visible change in the output
is noticed.
Press “Start” on the turbo pump controller.
The turbo pump will pump down in stages. Each stage must meet a certain criteria
specified by the manufacturer. When the pump completes the final stage a message
stating “Normal Operation Reached, 75 kRPM”.
Actuate valve 12 on the valve control toolbar in FPG Tool (see Section 6.4.3) to expose
the sensor to vacuum.
Continue pumping for at least 8 hours.
Log the vacuum reference sensor output. The value can be written by hand, or the
[Run], [Run w/Point Log]
option can be used to log the data.
Once the value is recorded, turn the turbo pump off by pressing “Stop” on the controller.
Slightly open the turbo pump exhaust port.
The turbo pump changes audible frequency when going down in speed. Various sounds
coming from the turbo pump is normal.
Turn the roughing pump off.
To correct a zero offset, change the
[Config], [System Setup], <Vacuum reference
sensor offset>
(see Section 6.6.2.1) value to the logged offset value but with an
opposite sign. If the value is positive, enter a negative number and visa versa. Use the
[Accept]
button to store the changes prior to leaving the
<System Setup>
window.
Switch to user level (see Section 6.10).
