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gain of the measuring circuit
- change of measured quantity value.
Measuring probes are equipped with the temperature sensor and functions that
minimise the influence of the above-mentioned factors on the measured value.
1.4.1. Compensation of zero indication
Compensation of zero indication occurs after zeroing of the detector or the measuring
circuit. It is realised with the aid of the functions which the LMC-10 probe is equipped
with. For compensation of zero indication it is necessary to use the following commands
of the control device:
•
Zeroing of detector. The zeroing procedure of the detector consists in the
measurement of the dark current of the measurement probe detector and its
corresponding temperature. It can be conducted only with the covered reception
field of the probe. The value of the dark current and the temperature of the zeroing
are saved to the memory of the measurement probe.
•
Zeroing of measurement system. The zeroing procedure of the measurement system
consists in the direct measurement of the correction that results from the measuring
circuit offset voltage which is deducted from the result. It is automatically conducted
after the probe is connected to the control unit and whenever the detector is zeroed.
The value of the correction and the temperature of the zeroing are saved to the
memory of the probe.
1.4.2. Temperature compensation of the result
Alongside the use of the high-class elements in the design of the meter, the LMC-10
probe is equipped with the automatic compensation system of the influence of the
environmental temperature on the measurement value. The temperature in which the
calibration is conducted is the reference to the correction factor being then calculated
for the current temperature. The influence of the ambient temperature on the
measurement value is virtually possible to be omitted for typical usage.
2. THE LMC-10 METER OPERATION
2.1. Preparations
•
Connect the LMC-10 probe to the control unit according to its instruction manual.
•
Start the measurement.
•
Check the zero indication with the covered reception field of the probe and
alternatively, conduct zeroing of the detector.
•
Remove the cap from the probe. The instrument is ready to operate.
2.2. Measurement
•
The stabilising cap should be put on the probe when larger surfaces are tested.
•
Set the result averaging time in the control unit. The more unstable in time the value
of the measured quantity is, the longer the time should be. In most applications the
sufficient averaging time amounts to 1s
•
Choose the automatic or manual change of the measurement range. It is
recommended by the manufacturer to turn on the automatic change of the range.
The manual control is intended for the procedures of checking linearity during
calibration or in specific conditions of measurement when the value of the measured
quantity changes in time to such an extent that the control unit cannot determine
the proper measurement range.
•
Place the measurement probe perpendicular to the measured surface.
