Lufft ARS31-UMB, Руководство пользователя

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ARS31(Pro)-UMB Operating Manual V9/03.2017
G. Lufft Mess- und Regeltechnik GmbH, Fellbach, Germany 8
4 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
4.1 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 9.3 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 9.1.1 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.
If there is no freezing temperature / salt concentration detected in a measuring cycle the
last identified freezing temperature will be delivered for the following 40 minutes (default:
40
– interval can be adjusted). During this interval the freezing temperature can only move
to 0°C if the sensor definitely detects clear water on the road.
The freezing temperature profile is smoothed by the sensor. This function can be disabled
using the UMB-Config Tool.
Data polling takes place through any desired host computer which supports any of the
communication protocols described in Section 6 and disposes of an RS485 interface.