The detection methods of insulation resistance meters (also called megohmmeters) and electronic measuring instruments usually involve multiple steps and precautions to ensure the accuracy of the measurement and the reliability of the instrument. The following is a detailed summary of these detection methods:

1. Detection methods of insulation resistance meters
Preparation before measurement
Cut off the power supply of the device under test and discharge it to the ground by short circuit to ensure that the device is not energized.
Clean the surface of the object under test to reduce the contact resistance and ensure the correctness of the measurement results.
Check whether the insulation resistance meter is in good condition and perform open circuit and short-circuit tests. When open circuit, shake the handle to make the generator reach the rated speed and observe whether the pointer points to the "∞" position of the scale; when short circuit, short-circuit the terminal "line (L)" and "ground (E)", slowly shake the handle and observe whether the pointer points to the "0" position of the scale.
Correct wiring
There are generally three terminals on the insulation resistance meter: L, E, and G. L is connected to the conductor part of the object under test and the earth, and E is connected to the shell or earth of the object under test. G is connected to the shield of the object under test or the part that does not need to be measured.
When measuring the insulation resistance of the line, the L column is connected to the line conductor, and the E column is connected to the ground. When measuring the insulation resistance of the motor winding to the ground, the L column is connected to the motor winding lead, and the E column is connected to the motor housing. When measuring the insulation resistance between windings, the L and E columns are connected to the conductors of the two windings respectively. When measuring the insulation resistance of the cable to the ground, the L column is connected to the cable core wire, the E column is connected to the cable surface, and the G column is connected to the cable insulation layer.
Measurement operation
Place the insulation resistance meter in a stable and firm place, away from large external current conductors and external magnetic fields.
When shaking the handle, the speed should be from slow to fast. When the speed reaches about 120 revolutions per minute, keep rotating at a constant speed. Read the reading after 1 minute, and read the reading while shaking. Do not stop to read the reading.
If the pointer points to zero when shaking the handle, it means that the insulation being measured may have a short circuit. At this time, you cannot continue to shake the handle to prevent the coil in the meter from heating and damage.
Post-measurement processing
After the reading is completed, the device under test will be discharged. The discharge method may be to remove the ground wire used in the measurement from the insulation resistance meter and short-circuit it with the device under test.
Record the measurement results and perform necessary analysis and processing.
2. Detection methods for electronic measuring instruments
The detection methods for electronic measuring instruments vary depending on the type of instrument, but generally include the following steps:

Appearance inspection
Check whether the appearance of the instrument is intact and whether there is any damage or deformation.
Check whether the display screen, buttons, interfaces, etc. of the instrument are working properly.
Functional inspection
Check whether the various functions of the instrument are normal according to the instrument's instruction manual.
Perform necessary calibration and debugging to ensure the accuracy of the instrument.
Performance test
Perform performance tests on the instrument using a standard signal source or test fixture.
Record the test results and compare them with the standard values ​​to evaluate whether the performance of the instrument meets the requirements.
Safety inspection
Check whether the instrument is well grounded to prevent electric shock or short circuit.
Check whether the power cord and plug of the instrument are intact, and avoid using damaged power cords or plugs.
Maintenance and care
Perform necessary maintenance and care according to the instrument's instruction manual.
Clean the instrument regularly to keep its appearance and interior clean.
Check whether the battery or power supply of the instrument is sufficient to ensure that the instrument can work properly.
3. Precautions
When measuring, ensure that the equipment and instruments under test are in a safe state to avoid electric shock or damage to the instrument.
When using an insulation resistance meter, pay attention to the speed and strength of shaking the handle to avoid measurement errors caused by too fast or too slow.
When using electronic measuring instruments, pay attention to avoid interference factors such as strong magnetic fields and strong electric fields to ensure the accuracy of the measurement results.
When calibrating and debugging, the instrument's instruction manual should be strictly followed to avoid instrument damage or measurement errors caused by misoperation.
In summary, the detection methods of insulation resistance meters and electronic measuring instruments involve multiple steps and precautions. In practical applications, the appropriate detection method should be selected according to the specific measurement requirements and instrument type, and the operation should be strictly followed in accordance with the operating procedures to ensure the accuracy of the measurement results and the reliability of the instrument.