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4.6 Standard Platinum Resistance Thermometer (SPRT)
Coefficients
The SPRT function of the CL3001 uses ITS-90 standard coefficients
as a basis for measuring a SPRT. The five custom coefficients are
entered as deviations from the standard coefficients, and as such, all
of them are set to zero at the factory.
The coefficients A- and B- represent the A
4
and B
4
coefficient,
obtained when the SPRT is calibrated at the triple points of argon,
mercury and water. This covers the 83.8058K to 273.16K subrange.
Coefficients A, B and C can represent different coefficients based on
which subranges of the SPRT has been calibrated. For example, if
the 273.15K to 933.473K subrange was used, A, B and C would
represent A
7
, B
7
and C
7
whereas if the 273.15K to 692.67K subrange
was used, A and B would represent A
8
and B
8
and C=0.
To enter the deviation coefficients for a custom SPRT:
a)
Select RTD measure mode as described in the preceding
section.
b)
Press the
key until the SPRT type is selected.
c)
Press the
key to display the action prompt
"SET(1)/RECALL(2)".
d)
Press
to select custom SPRT data entry.
e)
At the "ENTER MIN TEMP" prompt, enter the minimum
temperature limit for the custom SPRT, and press the
key.
f)
At the "ENTER MAX TEMP" prompt, enter the maximum
temperature limit for the custom SPRT, and press the
key.
g)
At the "ENTER RTPW" prompt, enter the nominal
resistance value (RTPW) for the custom SPRT, and press
the key.
h)
At the "ENTER COEFF A" prompt, enter the first (A)
deviation coefficient for the custom SPRT, and press the
key. To enter a coefficient that includes an
exponent, enter the mantissa, press the
and
keys to select the EXP function, enter the exponent, and
press the
key.
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Содержание CL3001
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