General usage of noise meter
Whether the noise meter is used correctly or not directly affects the accuracy of the measurement results. Therefore, it is necessary to introduce the use of noise meters.
1. Precautions
.Read the instruction manual before use to understand the usage and precautions of the instrument.
.When installing the battery or external power supply, pay attention to the polarity and do not connect it reversely. The battery should be removed if not used for a long time to avoid leakage and damage to the instrument.
.Do not disassemble the microphone to prevent it from being thrown or dropped. Keep it properly when not in use.
.The instrument should avoid being placed in places with high temperature, humidity, sewage, dust, air or chemical gases containing high concentrations of hydrochloric acid and alkali.
.Do not disassemble the instrument without authorization. If the instrument is abnormal, it can be sent to a repair unit or factory for repair.
2. Calibration of sensitivity
To ensure measurement accuracy, calibration is required before and after use.
Fit the sound level calibrator to the microphone, turn on the calibration power, read the value, adjust the noise meter sensitivity potentiometer, and complete the calibration.
3.Measurement method
When measuring, the instrument should select the correct gear according to the situation, hold both sides of the noise meter flatly with both hands, and point the microphone toward the sound source being measured. You can also use extension cables and extension rods to reduce the impact of the noise meter's appearance and the human body on the measurement. The location of the microphone should be determined according to relevant regulations.
For sound level meters used to measure noise, the meter response can be divided into four types according to sensitivity:
(1) "Slow". The time constant of the meter is 1000 ms, which is generally used to measure steady-state noise, and the measured value is the effective value.
(2) "Quick". The time constant of the meter is 125ms, which is generally used to measure unstable noise and transportation noise with large fluctuations. Fast gears are close to how the human ear responds to sound.
(3) "Pulse or pulse hold". The rising time of the needle is 35ms, which is used to measure long-duration pulse noise, such as punches, hammers, etc. The measured value is the maximum effective value.
(4) "Peak hold". The rising time of the needle is less than 20ms. It is used to measure short-duration pulse sounds, such as guns, cannons and explosions. The measured value is the peak value, which is the maximum value. Distance meter, altimeter, laser line meter, flow meter, GPS thickness meter, level meter, flat plate meter, waveform recorder, test fixture, voltage and current recorder, data collector, graph recorder, flow totalizer instrument
