Pressure Systems 9022 Manuel d'utilisateur télécharger pdf (Page 130)

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Measurement Specialties Inc. NetScanner System (9016, 9021, & 9022) User’s Manual

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4.6 Coefficient Storage

The various calibration functions described in Sections 4.2 through 4.4 update the active offset

and gain coefficients, respectively, in the module’s volatile main memory (RAM) only. These

newer calibration coefficients will be lost when instrument power is turned off. The Set/Do

Operating Options (‘w’) command may be used to also store these coefficients back in each

transducer’s nonvolatile memory. This command’s option index = 08 will store new offset

coefficients, while its option index = 09 will store new gain coefficients.

A user may read (and should verify) any new offset and/or gain coefficients after performing

each calibration adjustment command (i.e., by saving coefficient data returned in a command

‘h’ or ‘Z’ response), or the Read Internal Coefficients (‘u’) command may be used to read

them any time after calibration adjustment commands have been performed (see coefficient

indexes cc=00 and 01 for arrays aa=01 through 10). These “adjusted” coefficients may be

verified, and then saved by storing them in each transducer’s non-volatile memory with the ‘w’

command described above. Alternately, they may be verified and stored on the host computer’s

secondary storage, and later restored (if necessary) with the Download Internal Coefficients (‘v’)

command (same array/coefficient indexes as ‘u’).

4.7 Non-volatile Parameter Storage for “non-Digitally

Compensated” Pressure Sensors (9021/9022 ONLY)

4.7.1

This section describes the capability to download and store parameters to NetScanner_ System

9021 and 9022 modules for use in calibrating and/or identifying sensors that do not conform to

the serial data storage and retrieval format of digitally compensated PSI 9400 sensors. When

using other than digitally compensated 9400 sensors, two alternative methods are available to

allow for non-volatile storage of key parameters for sensors attached to a 9021 or 9022. The first

method applies when using a non-digitally compensated 9400 sensor without non-volatile

memory or when using a third party sensor. This method provides the capability to calibrate

sensor measurements on the NetScanner

 System module even though the sensor itself does not

have the ability to store parameter data.

Commands that “download” parameters write the value into volatile memory in the module.

This volatile copy of the parameter is not actually copied into non-volatile memory until the

‘w07’ command is issued. This provides the capability to test new parameters before

committing them to non-volatile memory. It is important to note that the ‘w07’ command stores

the entire block of non-volatile parameters for the module. The second method applies when

using a non-digitally compensated 9400 sensor that has non-volatile memory.

As part of module initialization, all channels are automatically checked for attached PSI 9400

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Pressure Systems 9022 Manuel d'utilisateur Page 130