Campbell Scientific 43347 RTD Temperature Probe and 43502 Aspirated Radiation Shield - Manual (Page 15)

43347 RTD Temperature Probe, 43502 and 41003-5 Radiation Shields
TABLE 4-2. 43502 Blower/Tachometer Connections
Color
43502 115 Vac/12 DC
Transformer
*CR10X
*CR1000
Red POS terminal/wire with
red heat shrink
Black NEG terminal/wire without
heat shrink
G G
White TACH spare terminal Control Port/
Pulse Control Port/
Pulse
Clear No Connect terminal/wire without
heat shrink
G Ground
(symbol)
* using CSI pn CABLE2CBL-L, or user-provided 2-conductor shielded cable
5. Datalogger Programming for the 43347-VX Probe
This section is for users who write their own datalogger programs. A
datalogger program to measure this sensor can be created using Campbell
Scientific’s Short Cut Program Builder software. You do not need to read this
section to use Short Cut.
This section covers the 43347-VX probe, where the –VX specifies that the
probe/cable is configured for a 4-wire half bridge measurement using an
excitation voltage. Programming examples for the 43347-IX probe are covered
in Section 6, 43347-IX Measurement using Current Excitation.
The 43347 temperature is measured with a four wire half-bridge measurement,
Instruction BRHalf4W in CRBasic dataloggers, or Instruction 9 in Edlog
dataloggers. The measurement applies an excitation voltage and makes two
differential voltage measurements. The first measurement is made across the
fixed resistor (Rf), the second is made across the RTD (Rs). The result is the
ratio of the two resistances (Rs/Rf), which is not affected by lead length.
The result from the measurement is converted to temperature by a custom
polynomial for calibrated temperature probes (Section 5.1, Programming for
Calibrated 43347-VX Probes), or the standard PRT resistance to temperature
conversion for uncalibrated temperature probes (Section 5.2, Programming for
Uncalibrated 43347-VX Probes).
The program examples include instructions to measure and store the
tachometer output frequency (Hz) of the 43502 aspirated radiation shield.
Storing the output frequency is a way to insure the blower is operational.
TABLE 5-1 shows the sensor wiring for the measurement examples in Section 5.1,
Programming for Calibrated 43347-VX Probes, and Section 5.2, Programming for
Uncalibrated 43347-VX Probes.
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