l-com SRAQ-G016 User manual

AMMONIA (NH3) GAS SENSOR MODULE
User Guide for SRAQ-G016
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M_L-com_SRAQ-G016_11/2022_R1.0
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Product Description
The SRAQ-G016 gas sensor module detects the presence and concentration of ammonia, as well as other harmful vapors such as sulfide and
benzene. Integrated circuitry produces a non-linear voltage signal corresponding to the gas concentration. With a detection range of 10 to 1000 ppm,
this industrial sensor can be used in areas such as public restrooms, manufacturing facilities, warehouses and other commercial buildings where
ammonia gas concentration is a concern.
Features
 Features MQ135 sensing element
 Highly sensitivity and accurate
 Low power consumption
 Wide detection range 10  1000 ppm
 Analog and TTL level outputs
 4 pin male header
Applications
 Mining industry
 Agriculture industry
 Farming and Livestock industry
 Public restrooms
 Other IoT systems

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Technical Parameters
Electrical Diagram
 VCC is the 0  5 VDC power supply positive and negative; GND is the ground
 Aout is the analog output, Dout is the level output
 On the PCB, Indicator light on: Dout is low level. Indicator light off: Dout is high level
 The 1k resistor shown on the PCBA is the load resistance (RL), it can be changed by user.
Mounting Diagram
Mount the PCBA to the enclosure with screws. Hole diameter 3mm, pitch distances as per the diagrams given below.
Working Voltage 5 VDC ± 0.2 V
Working Current <150 mA
Gas Detection Ammonia, sulfide, benzene-based steam and other harmful gases
Detection Concentration 10  1000 PPM (Ammonia, toluene, hydrogen)
Preheating Time > 30 mins
Response Time ≤1 sec
Recovery Time ≤30 sec
Output Mode
Aout (Analog signal) 0  5 V (Non-linear)
Dout (Level signal) Low level: 0V; High level: 3.7V
Work environment
Temperature -10~50 °C
Humidity ＜95% RH

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Notes
1. Confirm the polarity and the voltage of the power supply before powering ON the sensor.
2. The analog output of this module is non-linear. When connect to microcontroller, it should be connected to ADC interface of the microcontroller.
3. The relationship between the resistance ratio and the concentration is a logarithmic relationship. For more info on typical sensitivity curve, check
MQ135 Probe on internet.
Typical Sensitivity Curve
The ordinate in the figure is the resistance ratio (Rs/Ro) of the sensor, and the abscissa is the gas concentration
Rs: The resistance value of the sensor in different concentrations of gas
R0: The resistance value of the sensor in 100 ppm ammonia gas
The calculation of the resistance ratio according to the output voltage is as follows:
The sensor is energized in relatively clean air for more than half an hour and after measure the output voltage value of Aout.
VCC is the power supply voltage, 5 VDC
RL is the load resistance
VRL = Aout = Vair value
When the sensor detects gas, the RS value can be calculated after measuring the value of Aout.
The VRL value at this time is the Aout value after gas is detected. It is different from the value of the above formula. The VCC value and the RL value
are the same as above.
The R0 and RS values are obtained, and the specific concentration value of the gas is converted by the RS / R0 value of the Sensitivity Characteristic
Curve.