DH Instruments PPCH, Operation And Maintenance Manual

Page: 49 / 192

3. OPERATION
Page 39 © 2009 DH Instruments, a Fluke Company
3.3 DIRECT FUNCTION KEYS
3.3.1 [RANGE]
 PURPOSE
To view and/or change the active pressure measurement range and associated settings.
[RANGE] selects from existing ranges. [AutoRange] creates new ranges (see Section 3.3.4).
 PRINCIPLE
A PPCH range is defined as a pressure span and associated settings (see Section 3.2.6).
A PPCH may have multiple ranges. Each Q-RPT (and the utility sensor if present) available
to the PPCH system has a default range which is its maximum full scale. Additional ranges,
lower than the Q-RPT’s full scale, may also be created using AutoRange (see Section 3.3.4).
Ranges created using AutoRange may be saved with all their settings for reactivation (see
Section 3.4.1).
The
[RANGE]
function key allows the active PPCH range and available ranges to be viewed
and selected.
 OPERATION
Pressing the
[RANGE]
function key activates the range viewing and selecting function.
When the
[RANGE]
function key is first pressed, the range identification screen for the active
range is displayed. For example:
1. Q-RPT or utility sensor designator.
2. Type of range.
<DF>
for the Q-RPT’s default range;
<AR>
for a
range created by AutoRange.
3. Q-RPT or utility sensor position designator.
4. Current pressure unit of measure.
5. Full scale pressure in current unit of measure in gauge and/or
absolute measurement mode depending on the measurement modes
available.
Active A70M DF IH
MPa 70g/70a
Pressing the
[+/-]
key or the
[RANGE]
key again while in the RANGE function toggles
through displays of the other available ranges, from lowest range to highest range.
To select a range to become the active range, press
[ENT]
while the desired range is
displayed. PPCH must be vented for the range change to occur. Press
[VENT]
if necessary
to complete the range change.
When selecting a range, if the range’s Q-RPT is an external Q-RPT and the PPCH cannot
communicate with it, PPCH displays
<Cannot find range’s external Q-RPT (Xn)>
(where
<Xn>
is the Q-RPT position designator). Use
[ENT]
or
[ESC]
to return to the range selection
screen. For information on setting up and communicating with external Q-RPTs see Section
2.3.9.1.
Pressing
[ESC]
while in the RANGE function returns to the MAIN RUN screen with no range
change having been made.
Range full scale limits are given in the pressure unit that is currently active for
that range. Change the active unit (see Section 3.3.1) to display the range limits in a different unit.