PPCH™ OPERATION AND MAINTENANCE MANUAL
© 2009 DH Instruments, a Fluke Company
Page 44
If an external Q-RPT that should be available is not being selected by AutoRange, use [RPT] to
search for Q-RPTs and determine whether external Q-RPTs have been properly connected and
initialized (see Section 3.3.5). The PPCH utility sensor (IuH) cannot be AutoRanged.
Accept proposed AutoRange:
To accept the proposed AutoRange and go the MAIN
RUN screen with the AutoRanged range active, press
[ENT]
or
[AutoRange]
.
To modify the AutoRange full scale, measurement mode or pressure unit of measure,
use
[ESC]
to back up through the AutoRange screens and make changes.
If you would like to use a Q-RPT other than the one selected by AutoRange, use
[RPT]
or the
cursor control keys to toggle through the choices available. Only Q-RPTs that can cover the
specified full scale and measurement mode are offered. Press
[ENT]
or
[AutoRange]
when the desired Q-RPT is displayed.
Before operating PPCH with external Q-RPTs, check carefully that the Q-RPT TEST(+) port is
connected to the PPCH TEST port. If the external Q-RPT is NOT connected to the PPCH TEST
port, it will not measure the pressure generated by PPCH and PPCH may reach a pressure higher
than the target pressure before its watchdog function recognizes that the external RPT is not
connected.
Take care not to overpressure external Q-RPTs when using them with a PPCH. When using
external Q-RPTs in RPM4s as reference pressure measurement devices with a PPCH, the user is
responsible to setting up hardware and following procedures to protect lower range Q-RPTs from
overpressure. Only the Lo Q-RPT (IL) built-into the PPCH is protected automatically.
To verify or confirm the active range from the MAIN RUN screen, use [+/-] or [RANGE] to
view the active range description (see Section 3.3.1).
See
Table 9 for a listing of all selections and settings affected by AutoRange and their
default values.
3.3.5
[RPT]
PURPOSE
Search for, initialize and display internal and external Q-RPTs available to the PPCH system.
PRINCIPLE
Up to six Q-RPTs can be included in a PPCH pressure controller/calibrator system, two internal and
four external (see Section 3.2.5). PPCH communicates with external Q-RPTs by RS232 over
its COM2 port.
To be available for use by the PPCH system, external Q-RPTs must be identified and
initialized. A Q-RPT search function occurs automatically each time PPCH power is cycled.
Also, pressing
[RPT]
initiates the Q-RPT search and allows the Q-RPTs that are available to
PPCH to be viewed. Use
[RPT]
to update the PPCH system configuration if you connect and
disconnect Q-RPTs without cycling PPCH power.
See
Section
2.3.9.1 for information on hooking up external Q-RPTs to a PPCH system.
