Pressure Systems 9022 - Manual (Page 26)

Pressure Systems, Inc. NetScanner™ System (9016, 9021, & 9022) User’s Manual
www.PressureSystems.com 2 - 9
Warning: Failure to provide proper purge supply pressure
will result in migration of moisture and contaminants into the
9016 module which can result in permanent damage to module
components.
2.3.6.2 CAL Mode Inputs
The 9016 model tubing plates contain inputs labeled CAL and CAL REF. When the module’s
internal calibration valve is placed in the CAL/RE-ZERO position, all DH200 transducer pressure
inputs are pneumatically connected to the CAL input port. All DH200 reference inputs are
pneumatically connected to the CAL REF input port. The CAL input may be used to perform
on-line zero adjustment of the transducers. The CAL input may also be used for DH200 span
adjustment calibrations and accuracy tests if appropriate pressure calibrators (such as the 903x series)
are available. Span calibration of multi-range scanners may also utilize the CAL port if the highest
applied pressure does not exceed the proof pressure rating of any other installed transducer,
otherwise the individual transducers must be calibrated with the valve in the RUN position.
When the internal calibration valve is in the CAL/RE-ZERO position, the RUN inputs (RUN REF
and numbered input ports) are pneumatically dead-ended to prevent migration of contaminants into
the instrument.
2.3.6.3 PURGE Mode Inputs
All standard 9016 models contain a purge/leak check option. The purge option allows users to apply
positive pressure to the PURGE input which will then be vented out of the user input ports, forcing
contaminants (such as moisture) out of the pneumatic input lines. Note that on common reference
9016 scanners, only the numbered input ports will be purged (RUN REF is not purged). True
differential 9016 scanners will purge both the run and reference input ports for all channels. The
purge supply provided to the 9016 must always be a higher pressure than the highest pressure
present on the input ports of the module. The purge supply must also be capable of
maintaining proper purge pressure at the high flow rates encountered while the module is in
the purge mode.
When commanded into the PURGE position, the purge input pressure will be connected to the
numbered measurement input ports allowing for a flow of air away from the instrument. The purge
cycle should be terminated by commanding the 9016 into a non-purge mode such as CAL. Purge
cycles should never be terminated by turning off the purge supply air while in the purge
position.