2. INSTALLATION
Page 9 © 2002-2007 DH Instruments, a Fluke Company
2.3.7 CONNECTING EXTERNAL Q-RPTS IN RPM4 REFERENCE
PRESSURE MONITORS
PPC3 can be connected pneumatically and by RS-232 to one or two RPM4 reference
pressure monitors to use up to four external Q-RPTs (two in each RPM4) as external
reference pressure measurement devices (see Section 3.2.4).
The PPC3 then manages communications and other RPM4 functions to integrate the RPM4
measurement capabilities into the PPC3 system. The RPM4 Q-RPT module’s Self Defense
System (SDS) is used to shut-off RPM4 Q-RPTs from the pressurized system when they are
not in use (see the RPM4 Operation and Maintenance Manual).
As a general rule, making the pneumatic connection between the PPC3 TEST port and the
remote Q-RPT as direct as possible favors good pressure control. As distance, volumes
and restrictions between the PPC3 TEST port and the remote Q-RPT are added, the
possibility of difficulty with pressure control when using the external Q-RPT increases.
To connect a PPC3 to an RPM4 to be used as part of the PPC3 system proceed as follows:
Set up the RPM4 for use as an external device to PPC3 following the instructions in
the RPM4 Operation and Maintenance Manual, Using RPM4 With a PPC3
Controller/Calibration Section.
Using tubing of appropriate pressure rating and a Tee, connect the RPM4 Q-RPT
TEST(+) port to the PPC3 TEST(+) port. The third leg of the Tee is for the connection to
the device or system under test. If there are two RPM4s, Tee the second RPM4 in series
with the first one. The order of the RPM4s on the test line is not relevant.
If an RPM4 Q-RPT will be used in a gauge pressure range of less than 100 kPa (15 psi),
consider connecting the RPM4 Q-RPT module TEST(-) port to the PPC3 TEST(-) port and
to the “low” connection of the DUT if available. This will improve pressure control and
stability when ambient pressure is unstable. If the Q-RPT is an Axxx designation Q-RPT,
this connection should be made but also be left open to atmosphere.
When external Q-RPTs are used with PPC3, the maximum set pressure is the maximum
pressure of the PPC3 controller/calibrator. The maximum pressure of the PPC3 is
determined by the PPC3 controller model or the Hi Q-RPT if one is installed (see Section 1.2.1).
Using a standard pin-to-pin DB-9M to DB-9F RS232 cable, connect COM2 of the PPC3
to COM1 of the RPM4 (see Section 4.2.1.3). If there are two RPM4s, connect COM2 of the
first RPM4 to COM1 of the second RPM4. The order of the RPM4 daisy chain is not
relevant.
Turn ON the PPC3 and RPM4(s).
Press [RPT] on the PPC3 key pad. This causes PPC3 to execute the Q-RPT search
function (see Section 3.3.5). Q-RPTs with whom communication is established will be
shown on the PPC3 display identified by their position (see Table 3).
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