Pressure Systems 9022 - Manual (Page 120)

Pressure Systems, Inc. NetScanner™ System (9016, 9021, & 9022) User’s Manual
www.PressureSystems.com 4 - 10
NOTE: When using the Configure/Control Multi-Point Calibration (‘C’) command,
only the local variables in the module’s volatile main memory (RAM) are changed.
Refer to Section 4.6 if it is desired to also store these new offset and gain
coefficients
in transducer non-volatile memory.
4.4 Integrated Multi-Point Calibration Adjustment
NetScanner ™ System Intelligent Pressure Scanners may have their accuracy enhanced by regular
application of one or both of the individual Re-zero and Span calibration adjustment functions
already described in Sections 4.2 and 4.3. For users who have installed scanner firmware version
2.24 or later, an integrated and more comprehensive Multi-Point Calibration function may be
used instead to adjust the same offset and gain coefficients for a module’s channels. This function
also provides for supplying additional calibration points, which is particularly useful when it is
desired to fit the adjustment data to the entire negative and positive range of the module. This
integrated calibration adjustment function is fully described in this section. It is implemented by
four (4) sub-commands of the ‘C’ command. Since this function combines the functions of the Re-
zero and Span calibration adjustments (using the ‘h’ and ‘Z’ commands) it is recommended that
you read the information of Section 4.2 and 4.3 before attempting to perform this multi-point
calibration.
It is recommended that a Multi-Point Calibration adjustment be performed whenever new
transducers are installed in your module. In such cases, the new zero and gain coefficients that
result should always be restored into the transducer’s non-volatile memory afterwards. In some
cases, the user’s application may not require such a comprehensive adjustment as the other factory-
determined pressure/temperature coefficients (stored permanently inside each transducer) are
extremely stable. Only an occasional Re-zero adjustment may be all that is necessary.
When instructed to execute a particular sequence of sub-commands of the Configure Multi-Point
Calibration (‘C’) command, the module will perform the various stages of the Multi-Point
Calibration adjustment calibration function, and then update both the offset and gain coefficients
in the module’s volatile (e.g., RAM) memory. The module will use this newly calculated data term
for all subsequent engineering-unit calculations.
4.4.1. Multi-Point Calibration Valve Control
Before executing a Multi-Point Calibration adjustment (using various forms of the
Configure/Control Multi-Point Calibration (‘C’) command), Model 9016 modules should have
their calibration valve placed in the proper position. For modules with only one common pressure
range for its transducers, the CAL position should be used since the span calibration pressure can