Campbell CS655 Manual de usuario descargar pdf (Pagina 12)

Model HFP01SC Self-Calibrating Soil Heat Flux Plate

6.2 Wiring

Connections to Campbell Scientific dataloggers are given in FIGURE 6-1,

TABLE 6-1, and TABLE 6-2. The output of the HFP01SC can be measured

using a single-ended analog measurement (VoltSE() or Instruction 1),

however, a differential analog measurement (VoltDiff() or Instruction 2) is

recommended.

The wiring convention is that the white wire is positive with respect to the

green wire, when energy is flowing through the transducer from the side with

the text “this side up” to the other side.

The switched 12 Vdc port can source enough current to calibrate

four HFP01SC plates. If additional HFP01SC plates are needed,

an external relay is required to power the additional plates (see

example 4).

NOTE

For dataloggers without a SW12V output (CR7X, 21X and CR10), a relay

(A21REL-12) is required for the in-situ calibration (see Example 4).

6.3 Programming

The HFP01SC has a nominal calibration of 15 W m

-2

-1

. Each sensor is

accompanied by a calibration certificate. Each sensor also has a unique

calibration label on it. The label is located on the pigtail end of the sensor

leads.

6.3.1 Example 1. Sample CR5000 Program Using a Differential

Measurement Instruction

TABLE 6-3 provides the wiring for Example 1.

TABLE 6-3. Wiring for Example 1

Description Color CR5000

Sensor Signal #1 White 15H

Sensor Signal Reference #1 Green 15L

Shield #1 Clear

Sensor Signal #2 White 16H

Sensor Signal Reference #2 Green 16L

Shield #2 Clear

Sensor Signal #3 White 17H

Sensor Signal Reference #3 Green 17L

Shield #3 Clear

Sensor Signal #4 White 18H

Sensor Signal Reference #4 Green 18L

Shield #4 Clear

1 2 ... 7 8 9 10 11 12 13 14 15 16 17 ... 33 34

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Campbell CS655 Manual de usuario Pagina 12