2. INSTALLATION AND SHORT TERM STORAGE
Page 13 © 1998 DH Instruments, Inc.
2.3.5 CONNECTING TO THE DEVICE UNDER TEST (TEST PORT)
See Section 2.3.5.1 before proceeding to connect the device under test.
Using a pressure connecting hose of appropriate pressure rating, connect the device or system to
be tested to the TEST port of the PPC2 AF. The PPC2 AF TEST connection is ¼ in. NPT female.
Minimizing the length of the test connection hose will enhance control performance and
reduce pressure setting time. For normal operation, the total volume of the device of
system under test including connecting tubing should be less than 30 in
3
(500 cc).
PPC2 AF pressure control will not operate properly if there are excessive leaks in the test
system (see Section 3.2.8).
PPC2 AF pressure may be adversely affected if the test connection hose is too restrictive.
For optimum results, the inner diameter of the connecting hose should be > 0.07” (1.75 mm).
NEVER apply pressure to the TEST port without having a pressure supply equal to or great than
the applied pressure connected to the SUPPLY port. When controlling pressure externally, or
measuring external pressure through the SUPPLY port, NEVER
cause the pressure to change at
a very rapid rate. For example, do not vent suddenly by opening an external valve. Internal
PPC2 AF damage may result.
2.3.5.1 INSTALLING THE SPLT
The SPLT (if provided) is intended to collect and exhaust liquid contaminants that may be
present in the device or system under test so that they do not return to the PPC2 AF.
The SPLT is installed in the test connection line at a low point between PPC2 AF and
the device or system under test. The SPLT pressure connections are 1/4 in. NPT female.
Teflon tape or another sealing material should be used to assure leak free
connection of adapters installed in the SPLT pressure connections.
Proper SPLT operation is dependent on the gas flowing through it in the correct
direction. Be sure to connect the SPLT to the device or system under test and
the PPC2 AF following the connector port labels on the SPLT.
Connect the SPLT electrically to the PPC2 AF rear panel DRIVER connection and to the
SPLT terminal blocs. See Appendix 9.2 for information on preparing the SPLT
electrical cable and connection to the SPLT terminal blocs.
The SPLT must be mounted vertically with the purge valve at the bottom to
perform properly. It must be at a lower point in the system than the PPC2 AF
and/or the device under test. In operation, liquid contaminants collected from the
device or system under test will be exhausted through the SPLT purge valve.
Liquid contaminants will be forcibly ejected from the SPLT purge tube. Provision
for collecting the purged liquids should be considered when installing the SPLT.
Excessively dirty or wet filter elements can adversely affect pressure control.
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