DH Instruments FPG8601, Operation And Maintenance Manual

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6. FPG TOOLS
Page 75 © 2007 DH Instruments, a Fluke Company
6.6.4 [INTERNAL LIMITS]
The
[Internal Limits]
is provided to change limits and setup information that are
typically constant. Changes may be necessary for diagnosing problems or to provide more
restrictive limits in an attempt to obtain a better overall uncertainty. Make edits to the desired
fields then press the
[Save]
button to accept the changes. Closing the display without
pressing
[Save]
ignores all changes.
A thorough understanding of all settings in the [Internal Limits] option is required prior
to making changes. Make sure all data is entered in the proper units with the correct
sign. Failure to accurately enter limit information can result in the FPG pressure always
indicating a not ready condition.
With the exception of the first tab, all tabs in
[Internal Limits]
allow the adjustment of limits
specific to a specific type of measurement. In most cases, the limits effect when FPG Tools
will provide a re-zero warning and force a “Not Ready” condition. Making a limit too small can
make it impossible to be “Ready” and making the limit too large can remove the power of the
limit all together. Sound limits are important to ensure that correction values associated with
a change in conditions remain small.
6.6.4.1 <SETUP>
The setup tab allows adjustment of diagnostics level setup parameters.
Figure 33. <Internal Limits> <Setup>
Table 20. <Internal Limits> <Setup>
Options
LABEL DESCRIPTION
Setup load cell
during
initialization
(check box)
When checked, FPG Tools re-initializes the load cell’s internal parameters
as part of the initialization process of any run mode. This option should be
checked whenever the load cell parameters were manually modified since
the last use of FPG Tools.
Use effective area
based on
measurement
mode
(check box)
Check this option to use the effective area setup in the
<FPG Calibration
Setup>
based on the current pressure measurement mode. This option
has no effect if the selected calibration file uses the same effective area for
absolute and gauge mode (see Section 6.6.3).
Apply thermal
transpiration
correction to the
vacuum
reference sensor
(check box)
Check this box to apply the thermal transpiration correction to the FPG8601
vacuum reference sensor. By default this value is not checked because the
vacuum reference sensor is not calibrated with the thermal transpiration
correction active. In general, do not use this feature for normal operation
without consulting DH Instruments Technical service.