Heated transducers - WMT700

WMT700 Series User Guide

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User guide

Heated WMT700 sensors have the following symbol.

SLD235227-A-Hazard Warning Label

The sensor can be hot during normal operation. Avoid touching the sensor in operation. The sensor may detect touching as an ice blockage and start the high power melting mode.

Do not touch hot surfaces. Wear protective gloves when working with WMT700.

Let WMT700 cool down for 20 minutes after disconnecting the heating power supply.

The heating functionality has a thermostatic control with temperature sensors in each transducer. The control function keeps the transducer temperature at 20 °C (68 °F) and adds heating power when necessary. If the sensor is blocked, WMT700 increases the heating power to melt the ice and returns to lower power after a period of time. The heating mode can also be activated at higher temperatures to distract birds or insects if the sensor detects a blockage.

You cannot change the heating parameters, but you can enable or disable the heating functionality with configuration parameters. When heating voltage falls below 18 V DC, an alarm is raised. Heating is automatically disabled if heating voltage falls below 15 V DC.

Regardless of heating voltage, the maximum heating power is limited to 40 W and the average heating power is limited to 32 W. The maximum power control is achieved by automatically sequencing the transducer heaters depending on a heating voltage.
  • At low heating voltages, all the transducers are heated simultaneously.
  • At mid-range, 2 of the transducers are heated.
  • At high voltage end, a single transducer is heated at a time.
A pulse width modulation (PWM) scheme is used to control the average heating power.
Figure 1. Heated transducers peak and average power