DH Instruments PPC4, Operation And Maintenance Manual

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2. INSTALLATION
Page 9 © 2009 DH Instruments, a Fluke Company

Caution
Never connect a pressure supply greater than 20 % over the maximum
pressure of the PPC4 Hi Q-RPT you are using (except when the Hi Q-RPT is
a BG15K Q-RPT). Be sure to connect the pressure supply to the SUPPLY
port. Connecting to another port can damage the PPC4.
2.3.5 Connecting A Vacuum Pump (Exhaust Port)
For PPC4 to set pressures under atmosphere and/or to reliably set pressure under 20 kPa (3 psi)
gauge (other than zero gauge), a vacuum supply must be connected to the
EXHAUST port.

Caution
•
Never connect a pressure supply to or plug the PPC4 EXHAUST port.
•
To avoid building up pressure on the EXHAUST port or on a vacuum
pump connected to the EXHAUST port, the vacuum source should
either be continuously ON or the EXHAUST port should be bypassed to
atmosphere when the vacuum source is OFF. This is because when a
supply pressure is applied to the PPC4 SUPPLY port and the PPC4 is
NOT in the vent ON condition, there is typically a constant gas exhaust
through the PPC4 EXHAUST port.
Note
To ensure optimum pressure control when changing the pressure applied
to the EXHAUST port from vacuum to atmosphere or vice-versa, be sure to
change the control reference setting if the setting is NOT in AUTO mode
(see Section 3.2.27.1).
2.3.6 Connecting External Q-RPTS In RPM4 Reference
Pressure Monitor
PPC4 can be connected pneumatically and by RS232 to a RPM4 reference pressure monitor
to use up to two external Q-RPTs in RPM4 as external reference pressure measurement
devices (see Section 3.2.5).
The PPC4 then manages communications and other RPM4 functions to integrate the RPM4
measurement capabilities into the PPC4 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).
Note
As a general rule, making the pneumatic connection between the PPC4
TEST port and the remote Q-RPT as direct as possible favors good
pressure control. As distance, volumes and restrictions between the PPC4
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 PPC4 to an RPM4 to be used as part of the PPC4 system, proceed as follows:
Note
Set up the RPM4 for use as an external device to PPC4 following the
instructions in the RPM4 Operation and Maintenance Manual, Using RPM4
with a PPCx Controller/Calibration Section.