This Regulation is applicable to type appraisal (or prototype test), initial verification, subsequent verification and in-service inspection of pressure transmitter (including positive/negative gauge pressure, differential pressure and absolute pressure).
2 References
The following documents are referenced in this Regulation:
JJF 1015-2002 General Norm for Pattern Evaluation and Pattern Approval of Measuring Instruments
JJF 1016-2002 The Rules for Drafting Program of Pattern Evaluation of Measuring Instruments
JJG 875-1994 Verification Regulation of Digital Pressure Gauges
GB/T 17614.1-1998 Transmitters for Use in Industrial-Process Control Systems—Part 1: Methods for Performance Evaluation
GB/T 17626.3-1998 Electromagnetic Compatibility—Testing and Measurement Techniques—Radiated Radio-Frequency Electromagnetic Field Immunity Test
While applying this Regulation, attention shall be paid to that the currently valid versions of the above references are applied.
3 General
The pressure transmitter refers to an instrument which converts the pressure variables into standardized transmissible output signals; where, both show a continuous function relationship as specified (linear function in general). It is mainly used for measurement and control of pressure parameters in industrial process; differential pressure transmitter is generally used for flow measurement.
Pressure transmitter is classified into electric and pneumatic ones. For electric type, the standardized output signal is mainly DC signal of 0mA~10mA and 4mA~20mA (or 1V~5V). For pneumatic type, the standardized output signal is mainly gas pressure of 20kPa~100kPa. Other standardized output signals of special requirements may be available.
Pressure transmitter generally consists of pressure sensing unit, signal processing and conversion unit. Some transmitters are additionally installed with display unit or with fieldbus function. The structure principle of pressure transmitter is shown in Figure 1.
Pressure transmitter may be classified into capacitive, resonant, piezoresistive, force/moment-balance, inductive and strain ones by principle.
