GB/T 18271.2-2017Process measurement and control devices -- General methods and procedures for evaluating performance -- Part 2: Tests under reference conditions (English PDF)

Foreword

GB/T 18271 "Process measurement and control devices - General methods

and procedures for evaluating performance" is currently planned to be issued

as follows.

- Part 1.General considerations;

- Part 2.Tests under reference conditions;

- Part 3.Tests for the effects of influence quantities;

- Part 4.Evaluation report content.

This Part is Part 2 of GB/T 18271.

This Part is drafted in accordance with the rules given in GB/T 1.1-2009.

This Part replaces GB/T 18271.2-2000 "Process measurement and control

devices - General methods and procedures for evaluating performance - Part

2 Tests under reference conditions". Compared with GB/T 18271.2-2000, the

main technical changes of this Part are as follows.

- UPDATE normative references; replace GB/T 17212-1998 with GB/T

2900.56-2008 (see Clause 2; Clause 2 of the 2000 edition);

- Delete the terms "device under test", "set point", "adjustability", "transient

overshoot", and "expected event" and definitions (3.1, 3.6, 3.15, 3.21, 3.22

of the 2000 edition);

- Adjust the term "maximum measured error" to "measured error" (see 3.7;

1 Scope

GB/T 18271 specifies general methods and procedures for conducting tests

and reporting on the functional and performance characteristics of process

measurement and control devices. The tests are applicable to any such devices

characterized by their own specific input and output variables, and by the

specific relationship (transfer function) between the inputs and outputs, and

include analogue and digital devices. For devices that require special tests,

GB/T 18271 should be used, together with any product specific standard

specifying special tests.

2 Normative references

The following documents are indispensable for the application of this document.

For the dated references, only the editions with the dates indicated are

applicable to this document. For the undated references, the latest edition

(including all the amendments) are applicable to this document.

GB/T 2900.56-2008 Electrotechnical terminology - Control technology (IEC

60050-351.2006, IDT)

3 Terms and definitions

The terms and definitions defined in GB/T 2900.56-2008, GB/T 2900.77-2008,

and IEC 60050 (300) and the following ones apply to this document.

Algebraic difference between the values of the upper and lower limits of the

measuring range.

4 Accuracy related factors

Generally, unless otherwise specified in the test programme, the test for

accuracy related factors shall be carried out with the adjustments set at the

settings A, B, C, D, listed below, and in accordance with Table 1 whenever the

span and/or the lower range value adjustments are adjustable further than the

adjustments for the manufacturing tolerances.

5 Dynamic behaviour

Step tests permit the measurement of the dead time, and give a qualitative

evaluation of the non-linearity of the DUT.

Testing shall be carried out with the span adjusted to the approximate mean of

the maximum and minimum span, and with the lower range value set

approximately at the mid-point of its permissible range of adjustment.

6 Functional characteristic

These tests are simple electrical safety checks. Their inclusion is not intended

as a formal assessment of the safety of the equipment, nor are the required test

results intended as a design specification.

The DUT shall be set up for normal operation. The insulation resistance of each

input and output circuit shall be measured if it is insulated from earth.

7 Drift

The device shall be operated for 30 days and, where practical, a steady input

signal corresponding to 90 % of span shall be maintained. The span should be

adjusted to the approximate mean of the maximum and minimum span, and

with the lower range value set approximately at the mid-point of its permissible

range of adjustment.

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