Lufft 8610.U050, Operating Manual

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Operating Manual ARS31(Pro)-UMB
G. Lufft Mess- und Regeltechnik GmbH, Fellbach, Germany
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2 Differences between ARS31Pro-UMB/ARS31-UMB
ARS31Pro-UMB compared with ARS31-UMB possesses the following features:

Measurement of threat of icing by means of a direct measurement or freezing
temperature.

Exact measurement of road surface temperature with an external temperature
sensor.
3 Device description
Active Road Sensor ARS31Pro-UMB/ARS31-UMB serves to determine the freezing
temperature of a liquid on the road surface. It can be used to measure the following data:

Salt concentration (NaCl, CaCl and MgCl)

Product concentration (potassium acetate, potassium)

Freezing temperature (independent of mixture)
The sensor excels further due to the following features:

Compact design and easy installation

Low maintenance

Parts can be replaced without uninstalling the device

Data transfer via RS485

Internal electrical isolation of power supply

ESD protection on all interfaces

Inverse-polarity protection
3.1 Method of operation ARS31Pro-UMB/ARS31-UMB
ARS31Pro-UMB/ARS31-UMB determines the freezing temperature of a liquid on the road
surface by means of active cooling and heating. The Sensor allows precise determination
of the freezing temperature in the absence of accurate knowledge of the type or mixture of
salt.
The sensor operates in a temperature range described in the chapter 8.3 Operating
conditions.
The freezing temperature is calculated for road surface temperatures of less than 5°C
(adjustable between 2°C and 10°C). The lowest possible freezing temperature that can be
calculated is about 20°C below the current road surface temperature, for details see
chapter 8.1.1 Freezing temperature.
The sampling rate for freezing point measurement in the sensor is configurable and may
be set to 20, 30 or 60 minutes (factory settings: 20 minutes).
If the ambient conditions so
require, the sensor extends its measurement cycle by up to 10 minutes if necessary.
To avoid measurement gaps due to interference during measurement, the sensor is
equipped with an intelligent “hold measurement” function for freezing temperature.