Low concentrations of methane sensor GJC4 GJC4 (B) coal mine methane sensor for detecting low concentrations of coal mine methane content in the air. Mainly by black and white element that detects the bridge, operational amplifiers, A / D converter, microcontroller and display, output and other components. GJC4 sensor is an intelligent instrumentation, with auto-zero, auto sensitivity, nonlinear compensation function (all functions can be achieved by remote control), with high precision, easy to use, stable and reliable. With various domestic and international coal mine methane power meter monitoring system and other ancillary uses. The main technical indicators proof type: Mine intrinsically safe and explosion-proof mark: ExibdI measuring range: 0 ~ 4.00% CH4 measurement error: 0 ~ 1.00% CH4 δ ≤ 0.10% CH4 1.00 ~ 3.00% CH4 δ ≤ true value ± 10% 3.00 ~ 4.00% CH4 δ ≤ 0.30% CH4 response time: less than 20s alarm point: 0.50 ~ 3.50% CH4 can be set Alarm: red lights flashing, buzzer output signal: Frequency 200 ~ 1000Hz current 1 ~ 5mA RS485 interface, transfer rate 1200bps power output: 0/5mA current pulse Operating voltage: DC9 ~ 18V Current intrinsically safe: DC18V ≤ 100mA Jining Branch-mining equipment, large favorably, please call