GJC4(C) Coal mine methane sensorDetailed product description：

GJC4 (C) coal mine methane sensor (hereinafter referred to as sensor) is an intelligent detection instrument used to detect the methane content in the underground air of coal mines. Zero adjustment, sensitivity, nonlinear compensation, and other functions can all be achieved through a remote control, which has the advantages of high accuracy, stability, reliability, and ease of use. Not only can it be used in conjunction with our company's KJ70N monitoring system, but it can also be used in conjunction with other manufacturers' coal mine monitoring systems.

Environmental conditions for use
The environmental requirements for the use of sensors are as follows:
a) Environmental temperature: 0 ℃ to+40 ℃;
b) Relative humidity: ≤ 95% (+25 ℃);
c) Atmospheric pressure: 80 kPa to 106 kPa;
d) In situations where there is no significant vibration or impact;
e) Wind speed: 0-8m/s;
f) In Class I situations where there is an explosive gas mixture underground in coal mines, but there is no corrosive gas that can damage insulation.

Main technical indicators of GJC4 (C) coal mine methane sensor
Output signal:
Frequency analog quantity a) Frequency range of 200Hz to 1000Hz; b) When the pulse width is greater than 0.3ms, the voltage in the high-level state should not be less than 3V, and the voltage in the low-level output state should be less than 0.5V; c) When the transmission distance is 2km, the basic error of the sensor should not exceed the provisions of 4.3. (MHYVR communication flexible cable with polyethylene insulation and polyvinyl chloride sheath used in coal mines, with a single core wire diameter cross-sectional area not less than 1.5mm2).
Output current signal:
a) Current range 1mA~5mA or 4mA~20mA; b) Load: Output 1mA~5mA at DC 18V, load 0~1000 Ω; Output 4mA~20mA load 0-250 Ω at 18V DC.
Output RS485 signal a) Transmission method: RS485 b) Transmission port: 1 channel c) Transmission rate: 2400bps d) Communication signal voltage peak to peak value: (2-10) V;
Response time: should not exceed 20 seconds.
Power supply voltage: DC 9V~24V.
Working current: less than 100mA at rated DC 18V.
Remote control distance: not less than 5m.
Alarm point: Set arbitrarily within the measurement range (factory set to 1.0% CH4).
Power off point: arbitrarily set within the measurement range (factory set to 1.5% CH4), power off outputs a high-level state, and pulls out a current of 2mA
The voltage shall not be less than 3V, and the voltage in the low-level output state shall be less than 0.5V.