Measurement Specialties 9116 user manual CAL Mode Inputs, Purge Mode Inputs

Pressure Systems, Inc. Model 9116 User’s Manual

2.3.6.2CAL 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-ZEROposition, 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-ZEROposition, the RUN inputs (RUN REF and numbered input ports) are pneumatically dead-ended to prevent migration of contaminants into the instrument.

2.3.6.3PURGE 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.

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.

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.

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