MODUK DEF STAN 66-31 PDF

Introduction and Scope

Electronic and electrical test equipment is used by the Services under various conditions. It is the purpose of this Standard to define the general requirements and the testing procedures necessary to establish the satisfactory performance of proprietary test equipment to meet the various categories of Service use. It is intended primarily to assist in the design, development and assessment of such equipment.

This Standard does not cover the requirements for Safety Test instruments. The requirements for Safety Test instruments are contained in Def Stans 66-6, 66-11 and 66-16.

The general, design and construction, electrical, programmable item and electromagnetic compatibility (EMC) criteria defined in this Standard are applicable to all proprietary test equipment intended for Service use.

For environmental purposes, test equipment is classified in six categories as detailed in section five.

Equipments which are to be approved for Service use must satisfy all the requirements of sections one, two, three and four of this Standard together with the environmental and appropriate electromagnetic compatibility requirements detailed in sections five and six of this Standard respectively.

The environmental tests detailed in this Standard in general are derived from BS 2011, but there are some modifications as appropriate in the case of test equipment for Service use.

This Standard does not define any of the electrical performance tests which shall be carried out at appropriate points in the testing programme, neither does it define the limits of degradation of performance in adverse environmental conditions.

All tests are mandatory except where otherwise stated in the following clauses, which also give details of tests not covered by BS 2011 and state the necessary conditions required for such tests to be carried out. All results are to be recorded.

During or after any of the environmental tests it may be found that performance cannot be achieved or that some design modification is indicated. Whilst a degree of engineering judgement is essential, any action will depend on the assessment of results; agreement and direction should be sought from the Responsible Authority. At each environmental test stage, performance tests shall be carried out to confirm that the equipment meets its general specification.

From time to time reference is made to the full or relaxed specification given in the equipment specification. There will often be cases where a parameter will have a close tolerance (full specification) over a temperature range of say 0°C to +40°C, whilst a less stringent but realistically useful tolerance (relaxed specification) is allowable from say -5°C to 0°C and +55°C to +40°C, eg the frequency accuracy of an oscillator, to allow for reversible thermal excursions in equipment performance.

A Procurement Specification may call for specific mandatory tests in addition to those defined in this Standard.