Fluke HART SCIENTIFIC 1502A Manuel d'utilisateur télécharger pdf (Page 25)

6.4.5 IPTS-68 Conversion

The IPTS-68 characterization converts resistance to temperature according to

the International Practical Temperature Scale of 1968. The applicable coeffi

cients are R

(“r0”), α (“ALPHA”), δ (“dELtA”), a

(“A4”), and c

(“C4”).

You can also select the temperature scale (“SCALE”) as IPTS-68 (“68”) or

ITS-90 (“90”). Selecting ITS-90 causes the temperature to be adjusted by a

small amount equal to the difference between the ITS-90 and IPTS-68 tempera

ture scales.

6.4.5.1 Setting the Characterization Coefficients

Probe characterization coefficients are set within the Probe menu after select

ing the probe characterization type. Each coefficient appears with its name

shown briefly followed by its value. For example,

+4.336079

For some coefficients, you only need to set the digits in the number. Other coef-

ficients also have a sign as shown above (positive sign appears as “+”). Use the

L and R buttons to move between digits (and the sign). The selected digit

will flash. Use the U and D buttons to change a digit. Once the sign and digits

are correct, press Enter to accept the number. If you decide you would like to

cancel any changes you have made, you may do so by pressing the Ω/Exit but-

ton. This will immediately skip to the next coefficient.

If the coefficient also requires an exponent, it will appear after setting the num-

ber as follows:

E -04

Increase or decrease the exponent using the p and q buttons. Once the exponent

is correct press Enter to accept it.

6.4.5.2 Testing the Coefficients

The 1502A provides a convenient method for testing the coefficients you have

entered to make sure they have been entered correctly. This is done by calculat

ing temperature for given resistances and comparing the results with tempera

tures listed on the probe’s calibration report. This conversion test function is

located at the end of the Probe menu. After setting the coefficients “tESt”ap

pears briefly followed by the resistance value. You can change the resistance by

using the L and R buttons to move between digits and the U and D buttons

to change a digit. After setting the resistance press Enter. The 1502A will cal

culate and display the temperature corresponding to the resistance you entered.

6 General Operation

Selecting the Probe Characterization

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Fluke HART SCIENTIFIC 1502A Manuel d'utilisateur Page 25