Operating instructions

AMC-210 Transmitter with external electrochemical sensor
14
RECALIBRATION
For full recalibration adjustments, follow the Set-Up procedure steps 1 to 9 inclusive. There are
two adjustments to be made for periodic recalibration: Zero and Span.
Zero: While there is no gas present (clean air), the transmitter output signal current should
read 4 mA. This is obtained by adjusting the Zero trimmer on the transmitter. It is
possible, under certain conditions, that the Zero current will fall below 4 mA.
Alternately, set the integral display to read “zero” using the zero trimmer with no gas
present.
Span: While the sensor is exposed to the calibration gas sample, adjust the Span trimmer on
the transmitter to set the transmitter output signal current proportional to the applied
gas concentration.
FIGURE 6: Calibration/Verification Set-up