MGS-350 Manual
6509-9000 Rev 1
37
4.7. Calibration: Gas Method for EC Sensors
There are two adjustments required: the zero and the span. They are
performed on the sensor board but are monitored on the motherboard at
the 0-10V output.
IMPORTANT:
VR204 (not always fitted) is used to set the
bias voltage to the sensor and can be monitored between
TP0 (negative) and U2 Pin 3 (positive). THIS IS FACTORY
SET AND SHOULD NOT BE ADJUSTED.
Step
Calibrating Electrochemical (EC) Sensors
1
VR201 is used to adjust the zero of sensor. On the
motherboard, monitor the output between TP0 (negative) and
CON3 pin 3 (positive) and adjust VR201 until the voltmeter
reads 0 V or slightly positive (0.01 V is acceptable).
2
VR202 is used to calibrate the range (span) of the sensor. On
the motherboard, monitor the output between TP0 (negative)
and CON3 pin 3 (positive). Expose the sensor to calibration
gas. Allow a minimum of 3 minutes to stabilize and then
adjust VR202 until the voltmeter reads the voltage calculated
in section 4.4.