MT/T 781-1998General technical condition for high-resolution automatic earth resistivity instrument (English PDF)

3.1 General requirements

The instrument shall meet the requirements of this standard and be manufactured in accordance with the drawings and documents approved by the prescribed procedures.

3.2 Composition

The instrument consists of a transmitter, a receiver, and a power source.

3.3 Environmental conditions

3.3.1 The instrument should work normally under the following conditions.

a) Ambient temperature. -10 ~ 40 °C;

b) Average relative humidity. less than 90% (25 °C);

c) Atmospheric pressure. 80 ~ 106 kPa;

d) The surrounding environment shall be free of conductive and explosive gases and dust, and gases and vapors that may corrode metal parts and damage insulation.

3.3.2 The worst storage and transportation conditions that the instrument can withstand are.

a) High temperature. 70 °C;

b) Low temperature. -40 °C;

c) Vibration. acceleration 20 m/s2;

d) Shock. Peak acceleration 500 m/s2.

3.4 Electrical performance

3.4.1 Transmitter

3.4.1.1 Working frequency. 2 ~ 30

Set no less than three point frequencies in Hz, as specified by product standards.

3.4.1.2 Frequency stability. Guaranteed by temperature compensated crystal or other means, it should not be lower than 5 × 10-6.

3.4.1.3 The maximum supply current is not less than 1.5 A, and has over-current, short-circuit protection.

3.4.1.4 The transmitter shall have the function of automatic conversion of electrode power supply during measurement.

3.4.2 Receiver

3.4.2.1 Working frequency. It must correspond to the operating point frequency of the transmitter.

3.4.2.2 Inlet dynamic range. 10

V, but sensitivity must not be less than 100 µV.

3.4.2.3 Inlet equivalent noise. not more than 1

3.4.2.4 Suppression of maximum irrelevant level. 104.

3.4.2.5 Gain. 5 × 100 ~ 5 × 109, control in several steps.

3.4.3 Power supply. should not be less than 1.5

kW single phase 50

Hz, 220

V generator set provided. Can also take other reasonable power supply the way.

3.5 Structure and appearance

3.5.1 All screws and nuts must be tightened to prevent them from falling off automatically and vibration.

3.5.2 The appearance of the instrument must not be scratched, sunken or deformed. The enclosure shall have anti-rust measures.

3.6 Electrical safety

The instrument must be leak-proof. Its insulation resistance, working voltage, leakage current, etc. must meet the requirements of normal work and personal safety.

Claim.

3.7 Craft

Transformer rectifier power supply, printed circuit boards, etc. should be taken to prevent moisture, mildew, and insulation.

3.8 Environmental adaptability

3.8.1 The instrument should be able to withstand the high and low temperature working tests performed under the conditions specified in Table 1, and meet the requirements of 3.4.

3.8.2 The instrument should be able to withstand the high and low temperature storage tests performed under the conditions specified in Table 1.After the test under normal atmospheric conditions, it should meet 3.4 requirements.

3.8.3 The instrument should be able to withstand the humidity test under the conditions specified in Table 1. After the test, the instrument should be able to work normally.

Table 1

Test item temperature °C Test time h Recovery time Low temperature work test-10 2 Low temperature storage test -40 16 2 High temperature work test 40 2 High temperature storage test 70 16 2 Humidity test 40 °C, 90% RH 48

3.8.4 The instrument should be able to withstand GB/T After the test, the instrument should be able to work normally.

No obvious damage to the appearance.

3.8.5 The instrument should be able to withstand GB/T After the test, the instrument should be able to work normally.

No obvious damage to the appearance.

3.8.6 The instrument should be able to withstand GB/T after packaging 6587.6-1986 in the transport test specified in Group III conditions, there should be no obvious packaging after the test Damaged, the instrument should be able to work normally without obvious damage to the casing.

4.1 Test conditions

Unless otherwise specified in the environmental test or relevant standards, the test is performed under the following conditions.

a) Temperature. 15 ~ 35 °C;

b) Relative humidity. 45% ~ 75%;

c) Atmospheric pressure. 86 ~ 106 kPa.

4.2 Electrical performance test

4.2.1 Connect the dummy load indoors without opening the case.

4.2.2 The test block diagram is as follows.

4.2.3 The technical specifications of the test equipment should be compatible with the technical specifications of the instrument, and the precision should be an order of magnitude higher than the measured parameters.

4.3 Temperature test

Instrument according to GB/T 6587.2-1986 group III conditions for temperature test.

4.4 Humidity test

Instrument according to GB/T Humidity test was performed in Group III conditions of 6587.3-1986.

4.5 Vibration test

Instrument according to GB/T 6587.4-1986 group III conditions for vibration test.

4.6 Impact test

Instrument according to GB/T 6587.5-1986 group III conditions for impact test.

4.7 Transport test

After the instrument is packed, press GB/T 6587.6-1986 group III conditions for transportation test.

4.8 Basic safety test

Instrument according to GB/T the requirements of 6587.7 for basic safety tests should include three aspects of insulation resistance, voltage, and leakage current.

content.

4.9 Visual and structural inspection

Press MT

The provisions of Chapter 5 of 210-1990 are carried out.

5.1 Factory inspection

5.1.1 Each product must undergo factory inspection by the inspection department of the manufacturer. Qualified products shall be issued with a product certificate.

5.1.2 The inspection items are carried out according to the contents of the factory inspection listed in Table 2.

5.2 Type inspection

5.2.1 Type inspection should be carried out in one of the following situations.

a) When new products are trial-prototyped or old products are transferred to production;

b) If the structure, materials, and processes have changed significantly after the official production, which may affect the product performance

c) When production resumes after 1 year of suspension;

d) at normal production for 3 years;

e) when the quality of the product is unstable;

f) When the national product quality inspection agency requests a type inspection.

5.2.2 The inspection items are carried out according to the type inspection contents listed in Table 2.

Table 2

Inspection item requirements category test method factory inspection type inspection Appearance, structure, technology 3.5, 3.7 C 4.9 sqrt sqrt Electrical performance 3.4 A 4.2 sqrt sqrt High temperature operation 3.8.1 B 4.3 sqrt sqrt High temperature storage 3.8.2 B 4.3 × sqrt Low temperature operation 3.8.1 B 4.3 × sqrt Low temperature storage 3.8.2 B 4.3 × sqrt Damp heat 3.8.3 B 4.4 × sqrt Vibration 3.8.4 B 4.5 × sqrt Impact 3.8.5 B 4.6 × sqrt Transport 3.8.6 B 4.7 × sqrt Power frequency withstand voltage 3.6 A 4.8 sqrt sqrt Insulation resistance 3.6 A 4.8 sqrt sqrt Note.

The column with "sqrt" in the table indicates the items that must be tested, and "×" means no items.

5.2.3 One type shall be randomly selected from the qualified products during the factory inspection according to GB/T 10111.

5.2.4 Inspection and judgment rules.

a) For a category A project, if one item fails, the batch is judged to be unqualified.

b) For Category B items, if there are two unqualified items, the sampling inspection shall be doubled. If there are still two unqualified items, the product shall be deemed unqualified.

c) For category C projects, the reference project for inspection shall be determined according to the situation.

6.1 Signs

6.1.1 The product shall be provided with a nameplate, which shall include.

a) Product name and model;

b) the name of the manufacturer;

c) main technical parameters;

d) Date of manufacture and product number.

6.1.2 Packaging, storage and transportation marks shall comply with GB

Regulation 191.

6.2 Packaging

6.2.1 Product packaging should comply with GB/T

The requirements of 13384, specific packaging methods are stipulated by product standards.

6.2.2 Random documents should be attached when packing.The random documents include.

a) product certification;

b) instruction manual;

c) packing list;

d) other technical documents specified in the product standard.

6.3 Transport

6.3.1 The packaged product can be suitable for various transportation such as water, land and air transportation under the condition that it is not directly affected by rain and snow the way.

6.3.2 During transportation, avoid strong vibration and prevent falling.

6.4 Storage

The product should be stored at a temperature of -10 ~ 40 in a well-ventilated warehouse at °C, it should be checked regularly for long-term storage.