LIVAIR 7-24V Alpha Tracer Industry Instruction Manual
- May 15, 2024
- LIVAIR
Table of Contents
Instruction Manual
AlphaTracer
Industry
Modbus 485
7-24V Alpha Tracer Industry
Real-time radon measurements in humid rooms
The AlphaTracer is a professional, highly innovative real-time radon sensor
for fixed installation in smart buildings for connection to ventilation
controls or other devices suitable for analog or digital input signals. It
measures Rn-222 activity concentration in indoor air, which is provided as a
proportional digital output signal.
Sensor Specifications
| Technology | Lucas Cell |
|---|---|
| Initial measurement value | 10 min |
| Data interval | 10 min |
| Sensitivity | 17 cph at 100 Bg/m3 |
| Operation conditions | 0-60°C,RH <99 % |
| Measurement range | 0 – 1,000,000 Bg/m3 (0.2 – 27,000 pCi/l) |
| Precision | <±10 % at 370 Bg/m3 (10 pCi/l) |
| Accuracy | <±10% |
| Data communication | Modbus RS485 |
| Diffusion time | ~10 min |
General Device Specifications
Dimensions, Weight and Placement
Weight: 303 g
The sensor can be mounted in any conceivable position, as it is not sensitive
to humidity or vibration.
Calibration
Recalibration is recommended every 3 years. If the sensor is exposed to
very high concentrations (on average more than 1,000 Bq/m3), calibration is
recommended every 2 years. A factory calibration is offered by the company
LivAir GmbH. The sensor itself does not require any maintenance.
Safety and warning notices
Please read the data sheet carefully before commissioning the AlphaTracer. Damage caused by non-observance of the instructions in the data sheet is excluded from any liability.
- The radon sensor may only be installed by qualified personnel and must be installed in accordance with the data sheet.
- To avoid damage to the sensor, check that it has been connected correctly before applying the supply voltage.
- When unpacking, it must be checked whether the correct device version has been delivered.
- The AlphaTracer may only be used in the manner described in this operating manual. If the product is used in any other way, this may result in danger to the operator as well as destruction of the sensor.
- No technical modifications may be made to the sensor.
- The sensor housing should only be cleaned with a damp cloth. Do not use scouring agents or cleaning agents containing solvents.
- Furthermore, the sensor must not be used if the ambient conditions are not within the limits specified in the data sheet.
- The sensor must not be used in an explosive atmosphere.
- Failure to observe the safety instructions may result in damage to the sensor and injury to the user.
Power and Connectivity Options
| Power | 7-24VDC 16 mA |
|---|---|
| Communication | M12 plug |
There is a M12 connector to connect the sensor. As soon as the sensor is
supplied with voltage, the measurement starts.
Pin assignment
| Number | Connection |
|---|---|
| 1 | Shield |
| 2 | Vcc |
| 3 | GND |
| 4 | B- |
| 5 | A+ |
Pin assignment M12 male connector, 5-pos., A-coded, male side
Example for a M12 plug Connector – SACC-M12FS-5PL M
Manufacturer Part No: 1424653
Manufacturer: Phoenix Contac
M12 mounting with self-assembled cables
Chaining 
Correct example of four radon sensors in a row 
Incorrect wiring Modbus RS485
Each sensor connected to the bus is assigned a unique address. This must be
set beforehand with a programming tool. All sensors require the same
transmission speed. 
Bus system cable, Y distributor and termination
resistor (The components used can be found on the next page.)
Components
Cable Bus system cable – SAC-5P-M12MS/ 2,0-920/M12FS (2 Meters)
Manufacturer Part No: 1507557
Manufacturer: Phoenix Contact
Y Distributor Y distributor – SAC-5PY-F/M-F VP
SH
Manufacturer Part No: 141 9933
Manufacturer: Phoenix Contact
All pins of the Y distributor must be plated through 1to1
Circuit diagram Contact assignment of the M12 Y distributor
Termination resistor Termination resistor – SAC-5P-M12MS CAN TH
Manufacturer Part No: 1507814
Manufacturer: Phoenix Contact
Bus termination
Line polarization and line termination are a must for the Modbus RTU and ASCII
devices.
Aresistor is added in parallel to the “A” and “B” line of the receiver in
accordance with the characteristic impedance of the data line specified by the
cable manufacturer (120Ω is a common value). This value describes the
characteristic resistance of the transmission line and is not dependent on the
line length. Terminating resistors of less than 90Ω should not be used. The
terminating resistors may only be placed at the outer ends of the data line
(see resistors RT1 and RT2 in the termination diagram), and in a system
without repeaters no more than two terminations should be placed 
The
transmission line must be terminated with a resistor 120 Ohm / 0.25 W at the
respective last receiver of the Modbus transmission line. This resistor must
be inserted directly between the two signal lines before the input of the last
receiver circuit. Only shielded cables with twisted wires should be used for
Modbus.
Please supply the AlphaTracer only one time with voltage!
Modbus
| Driver Typ: | Modbus RTU |
|---|
Polling frequ. max [sec]:
Data bits
Stop bits
Parity
RTS| 180
8
1
none
disable
Timeout [ms]:| 500
Standard values to read out
Poll the sensor as seldom as possible!
Measured values only change every 10 min.
Too frequent polling (<1 min) can influence the measurement!
| 1* | 2-248 1*standard |
|---|---|
| 5* | 0=2400 I 1=4800 I *2=9600 13=19200 I 14=38400 |
| 16* | Radon value live 0-2,000,000 Bq/m3 |
| 17* | Radon value 24h 0-2,000,000 Bq/m3 |
| 18* | Radon value long 0-2,000,000 Bq/m3 |
| 19* | Radon entries [10 min] since start |
As default the sensor is using slave address 1. The radon value can be found
in register 20.
Example 1 – QModMaste
You can use the open source program QModMaster, which you can download here:
https://sourceforge.net/projects/gmodmaster
Just check which Com Port your USB to RS485 adapter is using. In our case it’s
COM11.
Select Modbus RTU… in the Options menu.
Set
Serial device to Com, Serial port to 4 and Baud to 9600 and go to Settings and
switch the Base Addr to 0. 
Set the Modbus Mode to RTU and Slave Addr to 1.
Important, put the Scan Rate to 10000 ms (which means every 10 seconds).
Normally we recommend to set the scan rate to 10 minutes, because the sensors
radon value is updated every 10 minutes. A faster scan rate just disturbs the
sensors radon measurement process. 
In this example, we read 7 registers at Start
Address 20.
- Radon value live 32bit
- Radonvalue 24h 32bit
- Radon value since start 32bit
- Radon entries since start 16bit
The radon value is in two registers because it is a 32bit value. Only a radon
value up to 65535 would be displayed there. At 65536 there is 0 and in the
next register then a 1. These are the high and low bytes of a 32bit register.
Define Function Code Read Holding Registers (0x03) and Start Address 0, Number
of Registers 7 and the Data Format Dec. Connect and activate Scan (so that the
tool automatically updates the information every 10 seconds). Now you can see
the sensor address in register 0.
How to change the slave id address?
If you want to use more than one sensor on the cable, then you need to give
each sensor its own address. By default each sensor is on the Modbus slave id
-
You can change the slave id as follows:
-
Select Function Code Write Single Register (0x06)
-
Now you can write for example the slave address to 7
-
Press the button Read/Write
If you
now try to read out the input register again, you will get an error message
because the tool cannot reach the sensor on Slave Addr 1, that means that the
change of the slave address has worked. 
Let’s change the Slave Addr to 7 and the Start
Address to 20 and test again. 
As a result the connection works and we get the radon
live value on address 20.
Example 2 – Rilheva Tool
There is a free version called Rilheva Modbus Poll that you can download here:
https://www.rilheva.com/rilheva-modbus-poll-desktop-
edition
Comparative measurement
In
this example, we have induced (under laboratory conditions) a very rapid
increase in the Radon-222 activity concentration from 30 to over 2,500 Bq/m3:
Both AlphaTracer variants show, only delayed in time, the same total exposure
as the reference instrument AlphaGuard (approx. 15,000 Euro acquisition cost).
Thus, the AlphaTracer Office reaches the measurement curve of the reference
instrument with a time delay of approx. 30 min, the AlphaTracer Industry with
a delay of approx. 100 min due to its 1P54 class.
A very fast increase or decrease of the radon concentration leads to a delayed
reproduction of the concentration change for radon measuring instruments with
a denser housing and consequently slower air entry, but the correct
measurement of the total exposure is not falsified or impaired by this.
Get in contact with us!
www.livair.ig
info@livair.ig
LivAir GmbH « Agnes-Pockels-Bogen 1 + 80992 Miinchen
© 2023 LivAir GmbH
References
- LivAir - betriebliche Gesundheitsförderung und Schutz vor Radon
- LivAir - betriebliche Gesundheitsförderung und Schutz vor Radon
- QModMaster download | SourceForge.net
- Livair (@livair.io) • Instagram photos and videos
- SAC-5P-M12MS/ 2,0-920/M12FS - Bus system cable - 1507557 | Phoenix Contact
- SAC-5P-M12MS CAN TR - Termination resistor - 1507816 | Phoenix Contact
- SAC-5PY-F/M-F VP SH - Y distributor - 1419933 | Phoenix Contact
- Rilheva Modbus Poll FREE Modbus RTU | Rilheva IIoT Platform