Campbell Scientific HFP01SC Hukseflux Self-Calibrating Soil Heat Flux Plate - Manual (Page 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).
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 mV -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 CR3000 Program Using a Differential
Measurement Instruction
TABLE 6-3 provides the wiring for Example 1.
TABLE 6-3. Wiring for Example 1
Description Color CR3000
Sensor Signal #1 White 9H
Sensor Signal Reference #1 Green 9L
Shield #1 Clear
Sensor Signal #2 White 10H
Sensor Signal Reference #2 Green 10L
Shield #2 Clear
Sensor Signal #3 White 11H
Sensor Signal Reference #3 Green 11L
Shield #3 Clear
Sensor Signal #4 White 12H
Sensor Signal Reference #4 Green 12L
Shield #4 Clear
NOTE
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