BEAMEX FB150 - Table 4 Matching Certificate Values To Its-90 Coefficients; Table 5 Setting Coefficients Rtpw, A8, B8, And B4

39
Controller operation
Main Menu
and “COEF B4”. These should be set with the corresponding values that appear on
the calibration certicate of the PRT. The parameter “RTPW” takes the triple point of
water resistance, often labeled “R0.01” or “R(273.16K)” on the certicate. Parameters
“COEF A”, “COEF B”, “COEF C” take the an, bn and cn coefcients where n is a
number from 7 to 11. Parameters “COEF A4” and “COEF B4” take the a
4
and b
4
coef-
cients on the certicate. Any ITS-90 parameter of the instrument that does not have a
corresponding coefcient on the PRT’s certicate must be set to 0.
The following table (Table ) shows which parameter to set for each of the coefcients
that may appear on the certicate. The example that follows demonstrates how to set
the ITS-90 parameters for certain cases.
Table 4 Matching Certificate Values to ITS-90 Coefficients
ITS-90 Coefficient Certicate Value
COEF A a7, a8, a9, a10, or a11
COEF B b7, b8, b9, or 0
COEF C c7 or 0
COEF A4 a4
COEF B4 b4
NOTE: If the certificate has two sets of coefficients, one set for “zero-power”
calibration and one set for 1 mA calibration, use the coefficients for the 1 mA
calibration.
Example 1:
A PRT was calibrated to ITS-90 and its calibration certicate states values for coef-
cients Rtpw, a4, b4, a8, and b8. Set the instrument’s parameters with values from the
certicate as follows.
Table 5 Setting Coefficients Rtpw, a8, b8, and b4
Coefficient Certicate Value
RTPW Rtpw
COEF A a8
COEF B b8
COEF C 0
COEF A4 a4
COEF B4 b4
5.2.4.1.1.3.1.1 PROG PROBE
The PROG PROBE parameter is used to tell the instrument to program a Smart Lemo
with the appropriate probe coefcients. Use the arrow keys to select “Yes” or “No”.
If “Yes” is selected, the Smart Lemo will be programmed with the appropriate coef-
cients for the selected conversion type. For ITS-90 and CVD, the coefcient values
need to entered before programming the Smart Lemo. For IEC-60751 and Resistance,
no values are required to program the Smart Lemo.