User manual

Hukseflux Thermal Sensors
HFP01SC Manual v0811 page 32/33
11 Appendices
11.1 Appendix on cable extension for HFP01SC
HFP01SC has 2 cables, one for the sensor, and one for the
heater.
It is a general recommendation to keep the distance between
data logger and sensor as short as possible. Cables generally act
as a source of distortion, by picking up capacitive noise.
HFP01SC cable can however be extended without any problem to
100 meters. If done properly, the sensor signal, although small,
will not degrade because the sensor impedance is very low. Also
connection of the heater is immune to cable extension.
Cable and connection specifications are summarised below.
Cable: 2-wire shielded, copper core (at Hukseflux we use 3
wire shielded, of which we only use 2 per cable)
Core
resistance
0.1 Ω/m or lower
Outer
diameter
(preferred) 5 mm
Outer sheet (preferred) polyurethane (for good stability in
outdoor applications).
Connection Either solder the new cable core and shield to the
original sensor cable, and make a waterproof
connection, or use gold plated waterproof
connectors.
Table 11.1.1 Specifications for cable extension of HFP01SC
11.2 Appendix trouble shooting
This paragraph contains information that can be used to make a
diagnosis whenever the sensor does not function.
It is recommended to start any kind of trouble shooting with a
simple check of the sensor and heater impedance. This test can
be found in chapter 5. The advantage of this test is that it can be
done even if the sensor is dug in.
The second thing to do is a check to see if the thermopile gives a
signal. The suggestion is to take a 9-15 Volt battery and to put it
across the wires leading to the heater. If these tests still did not
give any clue, please contact the supplier.