The testing method of portable gas measuring instruments for coal mines involves multiple links, including instrument preparation, parameter setting, on-site testing, data processing, and instrument maintenance and calibration. The following is a detailed description of these testing methods:

1. Instrument preparation
Check the power and charge:
Before use, first check whether the instrument has sufficient power.
If the power is low, it needs to be charged in time, and ensure that the charging process is carried out in a safe place.
Instrument structure understanding:
The portable gas detector is mainly composed of sensors, sound and light alarms, buttons, display windows, and detectable gas identification.
Make sure that each component functions normally and is not damaged.
2. Parameter setting
Power on and self-test:
Most portable gas detectors are turned on by pressing and holding the power button for a few seconds.
When the instrument is turned on, it will emit sound, light, and vibration alarm signals and enter the self-test mode.
Select gas type and measurement range:
On the initial interface, select the required gas type (such as methane, carbon monoxide, hydrogen sulfide, etc.) through the touch screen or buttons.
Set the appropriate measurement range according to the safety standards of the actual working environment.
Set alarm point:
Enter parameter setting mode and select alarm point setting.
Use the plus or minus key to adjust the high and low alarm point values, and press the power button to save the setting.
III. On-site detection
Sampling:
Place the portable gas detector in the environment to be detected to ensure that the instrument can fully contact the gas to be tested.
It is generally recommended to place the instrument at a height of about 1 meter from the ground to obtain more accurate measurement results.
For instruments with pump suction design, gas can be actively sucked for detection through pump suction.
Waiting for measurement:
The instrument will automatically perform gas detection and display the measurement results in real-time on the display.
Portable gas detectors usually provide fast measurement response so that users can understand the gas composition and concentration in the environment in a timely manner.
Record data:
Users can record the measurement results as needed for subsequent analysis and reporting.
Some high-end models of portable gas detectors support data storage and transmission functions and can export data to computers mobile phones and other devices for further processing through USB interfaces or Bluetooth.
IV. Data processing and alarm
Data processing:
Collate and analyze the measurement results to determine whether the gas concentration exceeds the standard.
If the gas concentration is found to exceed the standard, measures should be taken immediately to deal with it.
Alarm processing:
When the gas concentration exceeds the set safety range, the instrument will emit a sound and flash alarm.
After hearing the alarm, the gas concentration data on the instrument display should be checked immediately and corresponding protective measures should be taken.
V. Maintenance and calibration of the instrument
Daily maintenance:
In daily use, attention should be paid to the maintenance of the portable gas detector, such as cleaning the sensor gas chamber, checking the battery power, etc.
Avoid severe vibration or impact on the instrument to avoid affecting its performance.
Regular calibration:
To ensure the accuracy of the measurement results, the portable gas detector should be calibrated regularly.
The calibration work should be carried out by professional technicians to ensure the stability and reliability of the instrument's performance.
The calibration method usually includes calibrating the instrument with a zero gas and a gas of a standard concentration and obtaining a standard curve stored in the instrument.
In summary, the detection method of portable gas measuring instruments for coal mines involves multiple links and needs to be operated in strict accordance with relevant standards and specifications. By properly using and maintaining the instrument, the accuracy and reliability of the measurement results can be ensured, providing a strong guarantee for the safe production of coal mines.