8. GENERAL MAINTENANCE
Page 123
© 2007 DH Instruments, a Fluke Company
8.3.1
SET – UP
This process explains how the fixture needs to be set-up prior to calibration. The entire setup
should be on a flat and level surface. Use the
<Diagnostics Display>
on FPG Tools to
monitor the output of the vacuum reference sensor.
Attach the roughing pump to the exhaust port of the turbo pump.
Attach KF40 to KF16 adaptor the to top of the turbo pump.
Attach a KF16 elbow or tee to the top of the KF40 to KF16 adaptor.
Do not remove the isolation valve from the vacuum reference sensor. Remove the entire
valve and sensor assembly from the mounting post of the FPG. The pneumatic connection
from the valve to the FPG base is still required to open the valve when zeroing.
Attach the open port of the isolation valve (and ion gauge if available) to the side of the
elbow or tee in the horizontal position.
If an ion gauge is used while zeroing, never turn on the power of the gauge until the
vacuum reference sensor indicates a pressure near vacuum. Most ion gauges are
damaged when repeatedly exposed to atmosphere while powered on.
Attach the loopback connector to port P1 on the back of the V70 controller.
If the loopback connector is not attached to P1 on the controller, the turbo pump will not
activate.
Use FPG Tools to monitor the output of the sensor.
Make sure that the exhaust valve on the turbo pump is fully closed.
Plug in the vacuum pump.
Plug in the turbo pump controller.
8.3.2
WARM-UP
The vacuum reference sensor should be connected to the FPG with the power on for 10
continuous hours prior to use. The warm-up time is needed so that the internal heater on the
sensor can become stable at 45
°
C.
8.3.3
TEST THE ZERO OF THE VACUUM SENSOR
This process allows the zero of the vacuum reference sensor to be verified by pulling it down
to vacuum using a turbo pump. The zero is critical in the FPG calculation of absolute
pressure. In the instance where the zero is out of specification, the offset must be entered as
[Config], [System Setup], <Vacuum reference sensor offset>
(see Section 6.6.2.1).
Make sure that FPG Tools is in factory mode (see Section 6.10).
After the 10 hour warm-up time is complete, turn on the roughing pump connected to the
turbo pump.
Make sure the turbo pump exhaust valve is closed.
Allow the vacuum pump to run for a couple minutes.
