Charged to open the cover of the detector, measuring the voltage between the lower right corner of the V+.V-, adjust the blue RW1 potentiometer on the right, so that it is 0mV. Measurement the current between GND and I+ , adjust the lower left corner of the ZERO potentiometer, so that it is 4mA

opening the detector cover,and put throng  the standard gas to gas sensor, adjust the upper left corner of the  blue potentiometer “SPAN”, so that the display value is the same with the standard gas value

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Check if the sensor is damaged. Check method: remove the sensor, measure the resistance between the red, white, black, the line resistance is less than 30 ohm, if greater than 30 ohms, the sensor burned out.