Measurement Specialties 9116 - Manual (Page 24)

Pressure Systems, Inc. Model 9116 User’s Manual
Page 15 www.PressureSystems.com
2.3.6.2 CAL Mode Inputs
The Model 9116 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 Model 9116s 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 Model 9116 scanners, only the numbered input ports will be purged
(RUN REF is not purged). True differential Model 9116 scanners will purge both the run and
reference input ports for all channels. The purge supply provided to the Model 9116 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 Model 9116 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.
Warning: Failure to provide proper purge supply pressure will result in
migration of moisture and contaminants into the Model 9116 module which can
result in permanent damage to module components.