DH Instruments FPG8601, Руководство по эксплуатации и обслуживанию

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4. GETTING STARTED
Page 31 © 2007 DH Instruments, a Fluke Company
If the DUT requires adaptations that require tubing, use the shortest tube length
possible with an inside diameter of at least 15 mm. If only smaller inside diameter tubing
is available, the test will require longer waiting periods prior to taking a point.
Select
<Use vacuum reference sensor for absolute mode correction>
under the
[Config], [System Setup]
menu on the FPG Tools software. (See Section 6.6.2.1.)
Turn on both vacuum pumps.
Change the FPG to absolute mode by selecting
[Units], [Absolute Mode]
from the main
menu in FPG Tools (see Section 6.9.2.2).
4.10.3 ABSOLUTE DIFFERENTIAL MODE
This procedure describes the setup of an absolute differential DUT using the FPG as a
primary standard and the VLPC as the pressure control device. To begin, the FPG and the
VLPC must be set up according to the gauge/absolute setup procedure (see Section 4.6) and
the FPG is currently running in gauge mode.
If you want to be able to measure the reference pressure on the FPG for monitoring
purposes or for thermal transpiration correction, the vacuum reference sensor should be
attached prior to going to absolute mode. Using the vacuum sensor in this mode is
optional. If there is no need to monitor the reference pressure, ignore steps related to
the vacuum reference sensor.
If the vacuum reference sensor is already attached to the FPG there is no need to power
down the FPG.
Turn the power off of the FPG.
Attach the vacuum reference sensor and isolation valve onto the front of the FPG.
Make sure the sensor is vertical..
Power on the FPG.
Observe the warm up time that is required for the reference vacuum sensor
(if necessary).
Determine what type of fitting(s) will be required to adapt from the Test (Hi) port of the
DUT to the KF16 upper left Test (Hi) port on the FPG.
Determine what type of fitting(s) will be required to adapt from the Test (Lo) port of the
DUT to the KF16 tee that is attached to the lower left Test (Lo) port of the FPG.
It is recommended that shut-off valves be placed on the high and low ports of the FPG
(see Figure 12). Adding these shut-off valves will allow a DUT to be changed while keeping
the FPG in absolute mode. In addition, by adding these valves it will be possible to keep
the DUT evacuated of gas while other FPG processes are taking place (zeroing,
purging, etc.).
Attach the DUT Test (Hi) port to the upper left port on the FPG, Test (Hi).
Attach the DUT Test (Lo) port to the lower left port on the FPG, Test (Lo).