Campbell-scientific 3WHB10K 3-Wire Half-Bridge Terminal Input Module Uživatelský manuál stáhnout pdf (Strana 6)

3WHB10K 3-Wire Half Bridge Terminal Input Module

3. Wiring

Shield

10 kΩ

Datalogger

or AG

or G

FIGURE 3-1. 3-Wire Half Bridge Used to Measure PRT

TABLE 3-1. 3WHB10K Connections to

Campbell Scientific Dataloggers

Function

Label/Lead

CR10X,

CR510

CR23X,

CR1000,

CR800, CR850,

CR3000

21X, CR7,

CR9000X

Excitation Black Wire E1 EX1 Excitation 1

V1 Reference H SE1 SE1 1H

V2 Sense L SE2 SE2 1L

Ground G AG

4. Programming Examples

The following examples simply show the two instructions necessary to 1)

make the measurement and 2) calculate the temperature. The result of the 3-

wire half bridge measurement as shown is R

, the input required for the

PRT algorithm to calculate temperature.

All the examples are for a 100 Ohm PRT in the 3WHB10K. The excitation

voltages used were chosen with the assumption that the temperature would not

exceed 50°C. Table 4-1 lists excitation voltage as a function of maximum

temperature and the input voltage ranges used with the different dataloggers.

Calculation of optimum excitation voltage is discussed in Section 5.1.

The multiplier shown is for a 100 Ohm PRT. The multiplier for a 1000 Ohm

PRT is 10.

1 2 3 4 5 6 7 8 9 10 11 12 13 14

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Campbell-scientific 3WHB10K 3-Wire Half-Bridge Terminal Input Module Uživatelský manuál Strana 6