Pressure Systems 9022 Instrukcja Użytkownika Pobierz pdf (Strona 125)

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

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4.5 9021/9022 Analog Calibration

Both the standard 9021 and the 9022 modules are used to make absolute analog measurements

from either the PSI 9400 transducers or third party analog output transducers. In order to maintain

the highest level of analog accuracy, the 9021/9022 is designed to allow its firmware to perform

automatic software calibration of the analog interface circuitry. This automatic, firmware

controlled calibration function minimizes analog offset and gain errors for each of the twelve

9021/9022 input channels. This auto-calibration function reduces analog measurement errors

resulting from long term or thermally induced component drift. Unless disabled through

software commands to the 9021/9022, this software calibration function will be constantly

performed by the 9021/9022 firmware, therefore maintaining consistent measurement

accuracy within the 9021/9022. In order to perform this software calibration function, the

9021/9022 contains one internal voltage reference network. This internal calibration standard is

designed to provide excellent long term and thermal stability. This use of a common reference

network reduces user or factory calibration of the 9021/9022 to a simple calibration of this one

internal reference network. The following procedures describe the methods for verifying analog

measurement accuracy and for calibrating this internal reference in order to maintain optimum

accuracy through the 9021/9022.

NOTE: When using the 9021/9022 with digitally compensated PSI Model 9400

transducers, the span calibration functions (for the 9400 transducers) can serve as a

method to correct both 9400 and internal 9021/9022 measurement accuracies.

Periodic use of this span calibration function can eliminate the need for the described

voltage reference calibration when using the 9021/9022 with digitally compensated

Model 9400 transducers.

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Pressure Systems 9022 Instrukcja Użytkownika Strona 125