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Example1: If the users want to measure the unknown copper or aluminum
material, the calibration uses the copper and aluminum standard test block, as
long as the test of copper and aluminum material has the similar temperature
coefficient with the standard test block(that is
-0.004
), the measured value is
correct.
Example2: If the user uses a standard test block replaced the standard test block
provided by the manufacturer but is similar to the material to be tested, , if the temperature
coefficient is the same as that of the material to be tested, the measured value is correct.
6.1.2.2
“Automatic temperature compensation ---temperature sensor” mode
This model must be inserted into the external temperature sensor, and measure and read
the stable temperature value of standard testing block or the measured material before
calibration and measurement. Also should choose to measure the temperature coefficient of
the material at the time of measurement, and then measure the conductivity. The operation
is relatively cumbersome, but applies to any occasions, has higher accuracy, such as:
①
Can be used on the occasion when temperature of the calibrated test block is
different from that of the material to be tested.
Example 1: Users use two calibration blocks (both are assigned the temperature
coefficient) to calibrate instrument under a temperature, measuring one of calibration blocks
with external temperature sensor (both testing blocks have the same temperature), select the
value until temperature stable (see 5.3.2.6). Then put the eddy current probe in the high and
low values of calibration block to calibrate instrument. After calibration, begin to measure
the temperature conductivity value of different materials. Same with the calibration, use
temperature sensor to measured temperature value first(see 5.3.2.5), then select the
temperature coefficient value a
0
(see 5.3.2.6), finally flat the eddy current probe on the
material to measure the conductivity value, instrument display two conductivity readings,
both of them are the conductivity values under the current temperature and under 20
℃
.
Example2: if users are using their own standard test blocks for calibration, first of all,
place the standard test block conductivity value and temperature coefficient numerical into
the instrument internal (see 5.3.4.5) and selected as high value or low value calibration
block, calibration and measurement method is the same as example1.
②
The temperature coefficient value of the material can be obtained by the
conductivity value measured of the mode.
Example: measure the temperature coefficient of material. Firstly measure and record the
conductivity value tested by the calibration instrument at 20
℃
stable conditions, then heating
constant the material in a certain temperature (not more than +40
℃
), measure the
temperature value and the conductivity value σ(TA) under the current temperature, according
to formula
)
20
(
)
20
(
)
(
1
T
T
σ
σ
a
can tested the temperature coefficient a of the material.
Summary of Contents for 2008 B1
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