Optional heating power - WAC155

WAC155 User Guide

Document code
M210822EN
Revision
F
Language
English (United States)
Product
WAC155
Document type
User guide

WAC155 also provides the sensors with a throughput and control of heating power, which can be connected if sensor heating is required. The heating power circuit is galvanically isolated from the operating power circuit.

The heating power connection requires an extra pair of wires. Since the required heating current for the WA15 series is typically 0.5 ... 1 A, it is most conveniently supplied from a local power source. WAC155 automatically connects heating power in temperatures below +4 °C (39.2 F).

There are two ways to connect the heating power, depending on the heating power supply available. The default way is to use a 40 V power supply and connect the heating elements of the sensors in series.

When connecting DC heating power, make sure you have the correct polarity of the X2 connector pins 1 and 2 (HT1+ and HT2-). AC heating power wires can be connected either way round.

You can use the 40 V power supply only when both sensors are connected. The sensor heating elements have a 40 Ω resistance each. The typical heating current is 0.5 A in a series-connected system with a 40 V power supply.

Figure 1. Heating power connection with 40 V power supply

If you use a 20 V power supply, you must connect the sensor heating elements in parallel. The following figure shows the parallel connection. In this case, the typical current demand is 0.5 A + 0.5 A = 1 A.

Figure 2. Heating power connection with 20 V power supply

When you only install one sensor, anemometer WAA151 or wind vane WAV151, you must use a 20 V power supply and replace the missing sensor heating element with a jumper wire. In this case, only 0.5 A is typically consumed.

Figure 3. Heating power connection for anemometer only
Figure 4. Heating power connection for wind vane only