MoTeC PLM - Manual (Page 19)

MoTeC Sensor Calibration 19
Sensor Calibration
Introduction
The NTK and Bosch lambda sensors are factory calibrated with a trimming
resistor embedded in the sensor connector. This resistor value can be read by
the PLM and used to calibrate the sensor readings for a new sensor.
As sensors age their calibration changes. To maintain accurate readings, the
PLM allows comparison of the measured O2 concentration in air against that of
the pure O2 reference in the sensor itself to calculate a new calibration.
Sensor calibration values in the PLM Setup software are expressed as either an
equivalent calibration resistor value, or as a gain factor. It is recommended that
all applications that require sensor calibration values to be measured and
recorded (such as workshops using multiple sensors) should use the gain factor
calibration number rather than the equivalent resistor. Support for equivalent
resistor calibration values is included for backwards compatibility with previous
PLM software.
Calibration Methods
There are four calibration methods available under the Setup | Sensor menu.
Use Measured Calibration Value
The factory calibration resistor is measured by the PLM and used to calibrating
readings. The factory sensor plug must be present to use this calibration
method.
Enter Calibration Value
A previously measured calibration value can be entered directly as either an
equivalent calibration resistor value or as a gain factor value.
Entered calibration values are useful when sensors are calibrated using the free
air calibration (O2 concentration). The results of the free air calibration can be
recorded for a particular sensor and then entered when the sensor is used with
another PLM.