Printed in USA 150313
Page 06
5.1 Calibration
Depending on the version and the control mode there are three different possibilities to calibrate the
transmitter:
5.1 Manual Calibration
5.1.1 Zero-point
•
Connect calibration adapter carefully to the sensor element.
•
Apply synthetic air (150 ml/min; 1 Bar (14.5 psi ) ± 10%).
•
Wait 2 minutes until the signal is stable, push button “Zero” for 5 seconds.
After successful calibration the measuring signal is corrected automatically. Depending on the
selected signal starting point the measuring signal shows the following values:
Signal start at 2 V or 4 mA 40 mV = 0 ppm
Signal start at 0 V or 0 mA 0 mV = 0 ppm
If the zero-point is out of the admissible range (> 20 mV at starting point 0% / > 60 mV at starting
point (20%) before calibration, there is no correction of the measuring signal. The sensor has to be
replaced.
•
Remove calibration adapter carefully by turning lightly. Check the sensor for correct mounting!
5.1.2 Gain
•
Connect calibration adapter carefully to the sensor element.
•
Apply calibration test gas (150 ml/min; 1 Bar (14.5 psi) ± 10%).
•
Wait two minutes until the signal is stable, adjust control voltage with potentiometer ”Gain” until the
signal corresponds to the calculated value ± 3 mV, see calculation section 5.2.3.
•
Remove calibration adapter with a careful light turn. Check the sensor for correct mounting!
By limiting the gain factor, calibration will not be possible any more when the sensitivity of the sensor
reaches a residual sensitivity of 30 %. Then the sensor has to be replaced.
5.1.3 Calculation of Control Voltage
Signal start 2 V / 4 mA
Control voltage (mV) = 160 (mV) x test gas concentration (% LEL) + 40 (mV)
measuring range (% LEL)
Signal start 0 V / 0 mA
Control voltage (mV) = 200 (mV) x test gas concentration (% LEL)
measuring range (% LEL)
Specifications subject to change without notice. | USA 151203 | Page 6 of 14
12700 Stowe Drive, Suite 100, Poway, CA 92064 | Ph: (858) 578.7887 & (888) GO.IN
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AT-3300_V3 – UserManual
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