SARAD Smart Radon Sensor User manual

Manual
Smart Radon Sensor
Radon monitor for building automation
Version January 2020
Referenced documents
Software-Manual Radon Vision
SARAD GmbH
Wiesbadener Straße 10
01159 Dresden
Deutschland
www.sarad.de
[email protected]

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Table of content
TABLE OF CONTENT ...................................................................................................................... 2
INTRODUCTION............................................................................................................................ 3
THE INSTRUMENT......................................................................................................................... 4
Controls................................................................................................................................................ 4
Power supply ....................................................................................................................................... 6
Main power supply........................................................................................................................... 6
Back-up batteries ............................................................................................................................. 6
Batteries replacement ......................................................................................................................... 8
SELECTION OF THE RIGHT LOCATION FOR EXPOSURE AND INSTALLATION...................................... 9
SELECTION OF THE RIGHT INTEGRATION INTERVAL ....................................................................... 9
MEASUREMENT ......................................................................................................................... 10
LED INDICATORS......................................................................................................................... 11
COMMUNICATION INTERFACES .................................................................................................. 13
RS-485................................................................................................................................................ 13
General........................................................................................................................................... 13
Selection of the transfer protocol, addressing .............................................................................. 13
Implemented functions.................................................................................................................. 14
USB..................................................................................................................................................... 15
ANALOGUE OUTPUT................................................................................................................... 16
4..20mA current loop......................................................................................................................... 16
ALERT SWITCH............................................................................................................................ 17
SUPPLEMENTARY EQUIPMENT ................................................................................................... 18
Pressure sensor.................................................................................................................................. 18
CO2gas sensor ................................................................................................................................... 18
DISPOSAL INSTRUCTIONS ........................................................................................................... 19
TECHNICAL DATA........................................................................................................................ 20
Smart Radon Sensor .......................................................................................................................... 20
Wireless switch .................................................................................................................................. 22

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Introduction
The Smart Radon Sensor is an innovative Radon monitor, designed for integration in building
automatization systems. Thanks to the broad spectrum of interfaces one can integrate the sensor
with relative small effort within an existing infrastructure. The high sensitivity allows for quick and
precise determination of Radon value, so the device is suitable for controlling the ventilation
systems.

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The instrument
Controls
Fig. 1. - Front panel controls
Fig. 2. - Bottom panel controls

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1
RS-485 port „D-“
2
RS-485 port „D+“
3
4..20mA current loop „-“(GND)
4
4..20mA current loop „+“ (Iout)
5
DC external power supply „-“(GND)
6
DC external power supply „+“ (12÷24V)
7
Switch output port 1
8
Switch output port 2
Tab. 1. - Ports definition of terminal block.

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Power supply
Main power supply
The smart Radon Sensor requires an external power supply in range from 12V up to 24V. The
maximal current consumption does not exceed 50mA (including 20mA of current loop’s maximal
signal and active LEDs, but without usage of the CO2 sensor).
The connection ports for a power supply are shown in figure 1 and defined in table 2. Two ports of
the terminal block with the description „DC-„and „DC+“, at the device`s front panel, are ground and
positive potential respectively. It is recommended to use the power supply unit with a galvanic
isolation for supplying the Smart Radon Sensor. The galvanic isolation is of importance in case the
analogue output is utilized AND the 0..20mA inputs of the data log system are referenced to the
ground potential (e.g.: the current signal is transformed into the voltage value through a defined
resist).
Back-up batteries
The device is equipped with an internal backup power supply (UPS) consisting of two LR3 (AAA)
batteries. This feature allows one to continue the measurement seamlessly if main power supply
failure occurs.
Without DC connection the backup will supply the device for approximately two weeks. In such
circumstances the current loop as well as (if present) CO2 sensor will be deactivated, and the LEDs
functionality will be reduced. If the cell voltage drops below 1,0V, then the current measurement will
be interrupted and the instrument enters the standby mode. Once the main powers supply recovers
or new batteries are placed, the stored measurement data will be accessible immediately.
The instrument accepts alkaline as well as NiCd or NiMH batteries. Attention! Do not use lithium-ion
batteries because their cell voltage is 3V or 3,6V. For maximum operational period we recommend
the usage of alkaline batteries which are optimized for low loads.
It is also recommended to insert the batteries prior to mounting the device and connecting the
terminal block. The placement of the batteries is described more in detail in the next chapter.
Important: The real time clock of the instrument must be set by software after inserting the
batteries. The rechargeable batteries cannot be charged once placed in the instrument. For
stationary operation alkaline batteries are recommended. In contrary to rechargeable batteries, the

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alkaline batteries do not suffer from excessive self-discharge process and therefore are able to keep
their initial electrical capacity for over 10 years.

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Batteries replacement
For battery replacement, the rear cover has to be removed. To do that, both screws (A in fig. 3) at
the backside must be unscrewed at first. After that, the cover can be detached by tilting as shown in
picture 4. Please, pay special attention to the correct polarity of the batteries when inserting them
(fig. 5). Change both batteries at the same time because differing charging levels may lead to failures.
Use always batteries of the same type.
Fig. 3. - Remove both screws (A) at the rear
panel.
Fig. 4. - Remove the rear cover. Tilt it at the
round edge as shown.
Fig. 5. - Insert batteries (AAA/LR3) left and right
(take care for right polarity!).

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Selection of the right location for exposure and installation
The instrument should be placed at a location which is representative for the indoor air quality of a
room. The incidence of direct light and exposure to strong heat sources should be avoided. For
permanent installation, the Smart Radon Sensor can be mounted on a wall using a wall mounting clip
(accessory). Attention has to be paid because the wall itself could be the origin of the Radon inside a
room. This would result in an increased concentration in the surrounding of the surface. Some
comparison measurements at the preferred mounting position and in the middle of the room (each
at least a few days under similar weather conditions) will show if this is the case or not.
When the mounting of the device is accomplished the terminal block can be wired. If the batteries
were replaced before the installation had taken place, the internal clock has to be set with Radon
Vision software over USB connection.
Fig. 6. –The wall mounting clip.
Fig. 7. - Smart Radon Sensor with the mounting
clip.
Selection of the right integration interval
It is possible to adjust the sampling interval of the Smart Radon Sensor between 1 and 255 minutes.
From the physical point of view it makes no sense to choose intervals shorter than 30 minutes
because the response time of the instrument is in that order. If the expected Radon concentrations
are in the range or less than the statutory reference level of 300Bq/m³, an interval of 60 minutes
(default setting) should be used. Frequent zero readings for individual sampling intervals indicate
that the chosen interval is too short.

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Measurement
The measurement starts autonomously after replacing the batteries or connecting the main power
supply. The first measurement result will be available as soon as the first sampling interval is
accomplished. Newly acquired values will be appended periodically to the previously stored results.
The measurement cannot be stopped by the user.
Each year the voltage of the batteries should be checked. This can be done e.g.: by using Radon
Vision software and USB connection. Older data in the memory, which are no more needed, can also
be deleted by means of the software.
Radon activity above alarm threshold value (which is settable) will be indicated by LEDs at the front
panel (fig. 1.). Simultaneously the alert switch will be activated. Please refer to the chapters: „LED
indicators” and „Alert Switch”.