16
4.5 Electrical connection of passive 16131.5: wiring diagram
16131.5 is a passive sensor that does not need any power. Cables generally act as a source of
distortion, by picking up capacitive noise. We recommend keeping the distance between a datalogger or
amplifier and the sensor as short as possible. For cable extension, see the appendix on this subject.
Table 4.5.1
Wiring diagram of 00.16131.501000
PIN
WIRE
00.16131.501000
Analogue millivolt output
1
Brown
heater
4
Black
heater
3
Blue
not connected
2
White
signal [+]
5
Grey
signal [-]
Shield mesh
shield
Note 1: The heater is a resistive heater element
Note 2: At the connector-end of the cable, the shield is connected to the connector chassis and
thereby to the sensor housing
4.6 Grounding and use of the shield
Grounding and shield use are the responsibility of the user. The cable shield (called shield in the
wiring diagram) is connected to the aluminium instrument body via the connector. In most situations,
the instrument will be screwed on a mounting platform that is locally grounded. In these cases the
shield at the cable end should not be connected at all. When a ground connection is not obtained
through the instrument body, for instance in laboratory experiments, the shield should be connected to
the local ground at the cable end. This is typically the ground or low voltage of the power supply or the
common of the network. In exceptional cases, for instance when both the instrument and a datalogger
are connected to a small size mast, the local ground at the mounting platform is the same as the
network ground. In such cases ground connection may be made both to the instrument body and to
the shield at the cable end.
4.7 Using heater of 00.16131.501030 and 00.16131.0501000
00.16131.501030 and 00.16131.501000 have an on-board heater. Heating the sensor contributes to
the dependability and accuracy of the measurement, helping to prevent dew and frost deposition. The
heater is typically switched on at night-time only. During daytime it is recommended to switch off the
heater. Note that using the heater without any additional ventilation may cause zero offsets.
External ventilation can be used to reduce or eliminate the effect of heating. Note that when the heater
is not used, it has no impact on the instrument specifications.
The integrated heater is a resistive element with a constant resistance. This means that the generated
heating power increases with the applied voltage. When the heater resistance R, and voltage V, are
known, the generated heater power P, is given by:
P = V
2
/ R
A heating power of approximately 1.5 W is typically sufficient. With a heater resistance of 95 Ω, as
specified in the specifications table, 12 VDC is required to generate this power.
