Fluke HART SCIENTIFIC 1502A Manuel d'utilisateur télécharger pdf (Page 21)

when all the digits are correct. If the password is entered correctly the first pa

rameter in the menu will appear.

6.4 Selecting the Probe Characterization

Before the 1502A can measure temperature accurately it must know how to cal

culate temperature from the resistance of the sensor. You must select a conver

sion type and enter the proper characterization coefficients. There are several

temperature conversion algorithms available. The one to use depends on the

type of probe you are using and its calibration. The conversion algorithms use

coefficients that characterize the sensor. Coefficients are determined when the

probe is calibrated. SPRTs and PRTs often use the ITS-90 algorithms and are

provided with ITS-90 characterization coefficients.

6.4.1 Setting the Probe Characterization Type

The probe characterization type and characterization coefficients are set in the

Probe menu. Press the Menu button (“SEt?” appears), then the C/Probe but-

ton. The menu name, “ProbE”, will appear briefly then the characterization

type. The probe characterization types are indicated on the display as follows:

Pr= t90 ITS-90

Pr= rtd Callendar-Van Dusen

Pr= t68 IPTS-68

Select the desired probe characterization type using the U and D buttons and

pressing the Enter button. After the characterization type is selected the char

acterization coefficients follow. The coefficients that appear depend on the

probe type that was selected.

6.4.2 Setting the Characterization Coefficients

Probe characterization coefficients are set within the Probe menu after select

ing the probe characterization type. Each coefficient appears with the name of a

coefficient 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 the digits (and the sign). The selected

6 General Operation

Selecting the Probe Characterization

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Fluke HART SCIENTIFIC 1502A Manuel d'utilisateur Page 21