Prerequisits Radio - IoT - M2M
In an IoT sensor or M2M modem, the antenna plays an important role in the transmission of data:
- 1/4 wave antennas (ANT868-14-MAR-S2 or ANT868-14S4.0) require a ground plane. Without it, the performance of the antenna will be almost zero. It is very important to install the antenna with a sufficient ground plane in order to achieve maximum efficiency.
- The antenna must always be placed upwards, high and free of metallic obstacles (leave a free diameter of at least 20cm and ideally 1m)
- Antenna cable connectors and adapters can cause significant losses in radio quality. Depending on the type of cable used, the loss will be greater or lesser [for lengths greater than 3m it is recommended to use the CFP10 cable ref (10mm diameter)].
Propagation of radio waves
Radio waves (RF stands for Radio Frequency) propagate in straight lines in several directions. The propagation speed of waves in a vacuum is 3.10m/s.
In any other medium, the signal is weakened by
Absorption of radio waves
When a radio wave encounters an obstacle, part of its energy is absorbed and transformed into energy, part continues to propagate in an attenuated manner and part may eventually be reflected.
Reflection of radio waves
When a radio wave encounters an obstacle, all or part of the wave is reflected, with a loss of power.
The reflection is such that the angle of incidence is equal to the angle of reflection.
Properties of media
MATERIAL ATTENUATION EXAMPLES Air None Open space, courtyard Wood Low Door, floor, partition Plastic Low Partition Glass Low Non tinted glass Verre teinté Medium Vitres teintées Water Medium Aquarium, fountain Living beings Medium Crowd, animals, humans, vegetation Bricks Medium Walls Plaster Medium Partitions Ceramic High Tiles Paper High Paper rolls Concrete High Load-bearing walls, floors, pillars Armoured glass High Bulletproof glass Metal Very high Reinforced concrete, mirrors, metal cabinet, lift shaft
LPWAN is an acronym for Low Power Wide Area Network.
LPWANs emerged in the 2010s as a new model for long-range, low-power wireless communication.
LoRaWAN, Sigfox, LTE-M or NB-IoT are all part of LPWAN.
IoT sensors [Sigfox - LoRaWAN]
ACW is the acronym of ATIM Cloud Wireless.
It is also the name of ATIM's IoT range: indeed the interest of IoT sensors is to send data wirelessly from remote sites to a centralized cloud in order to facilitate monitoring, energy efficiency, decision making, etc...
1. Check that the power supply is correctly connected to the product and switched on
2. Check if the product has been registered on the network (provisioned)
3. Check if the radio network coverage is available (e.g. with a tester or if it is an operated network, on the operator's website)
4. Check if the LEDs are flashing when transmitting
1. Check that your configurator version is up to date (Menu File -> Update).
2. Download the latest version on this page.
1. Check that the meter wires are not reversed and that they are properly connected in the terminal block
2. Check that your meter head is correctly sized for your use (litre or cubic metre)
3. Check that the output of your meter does not exceed 5V in the case of a push-pull output
All IoT sensors in the ACW range are configurable. Depending on the sensor model and version, configuration will be available via USB, Bluetooth and/or Downlinks. 1. USB and Bluetooth configurations are available through the ACW configurator available here. 2. Downlinks configurations (downlink messages) are available from most IoT platforms and/or from Sigfox or LoRaWAN backends
In order to get information from a LoRaWAN or Sigfox product, it must be registered on the network corresponding to the sensor: LW8 for LoRaWAN and SF8 for Sigfox.
To register a product on a LoRaWAN or Sigfox network, you need to be in possession of the identifiers or keys of your product: Atim provides the product keys by email with each order.
If you buy a product exclusively from Atim without its connectivity, then you will have to provide these identifiers to your Sigfox or LoRaWAN operator so that it can be linked to the network in question.
The LoRaWAN wireless communication protocol offers two different types of network architectures:
1. Operated or public network
An operator covers a territory through LoRaWAN gateways connected to a network core. As an administrator, any sensor aiming to connect to this network will need to obtain a subscription through the operator or an authorised reseller. The types of sensor subscriptions vary according to the operators, the number of data sent, upstream and downstream messages, etc.
2. Private or local network
A customer can install his own LoRaWAN gateway and administer it, thus having control over his network. In this case, and contrary to an operator network, there is no connectivity cost to pay per sensor. However, depending on the type of core network chosen for the LoRaWAN gateway, there may be a subscription fee.
Sigfox is an IoT communication protocol and also an international operator.
Therefore, for a Sigfox sensor to send data, it requires a subscription.
Sigfox subscriptions can be purchased from your national Sigfox operators.
The Codecs of the ACW sensors contain information about the formats of the data frames of the ATIM sensors.
These Codecs are in Java Script and allow, in addition to the corresponding User Guide, to decode the content of the data of our sensors.
The decoding is most often done at the level of the data acquisition-visualisation platform.
The start-up process of the ACW range of IoT sensors is done by magnet.
All the sensors are delivered in "Deep Sleep" mode in order to save batteries, facilitate Plug&Play and avoid the phenomenon of battery passivation (significant loss of battery voltage if the batteries are not stimulated from time to time following the start of chemical reactions and if the sensor is not used, in stock for example).
In order to start an IoT sensor on batteries, you just have to approach the magnet for 6 seconds according to the position indicated on the User Guide of the product.
During these 6 seconds, the product should flash WHITE and then GREEN at the end of the 6 seconds to indicate that the product has started.
The ACW then enters the network pairing phase. During this phase, a FUSCHIA light signal with a fade effect indicates that the search phase is in progress.
If the connection is successful, the product will emit a light signal indicating the quality of the network:
- GREEN light: good network quality
- YELLOW light: average network quality
- ORANGE light: poor network quality
- WHITE light: no information on network quality
All ACW sensors in DIN format require an external 10-30 V power supply and an antenna to operate correctly.
The antenna is an essential part of the sensor to maximise the range and quality of the data transmission.
ACW/DIN sensors have an SMA connector that allows the connection of 868 MHz antennas. Many different connectors and adapters are available if the desired antenna does not have an SMA connector.
The advantage of connecting all types of antennas to ACW/DIN sensors is that they can be offset by a cable antenna: the antenna can then be positioned at a high point to maximise the quality of reception of the network signal.
Radio modem [M2M]
ARM is the acronym for Advanced Radio Modem.
It is also the name of the ATIM M2M range: indeed the ATIM M2M radio modems allow the transmission of data from a transmitter to a receiver in wireless thanks to a powerful radio module.
These modems allow the transmission of modbus RTU or TCP data, digital or analogue inputs and outputs.
This indicates that the equipment connected to the ARM-SE is not at the right speed, in fact the ARM-SE supports a maximum speed of 10Mbps and this happens if it receives frames at 100Mbps for example.
In this case, you just have to set the speed of your equipment to 10Mbps or automatic. On a PC, you need to set the network card speed to AUTO.
The Unitelway protocol used on serial links allows communication between a master device and one or more slaves.
The dialogue is always initiated by the master and no slave can decide to speak without the master having given it to him.
The master thus cyclically interrogates each slave in order to assign them a speaking time.
If the slave does not respond to this type of request, the master passes the floor to the next slave after a timeout.
If the communication is via an ARM radio link, the timeout must be increased on the master side due to the transmission delays of the radio modems.
For safety reasons, it is recommended to set this parameter to 100ms.
By default, to access the modem’s configuration via web pages or to use its radio channel, the machine connecting to it must be configured in the same IP address class. In the case of a link between two networks of different class, it will be necessary to modify the modem’s subnet mask (the modem does not act as a router). This also has the advantage of filtering a class of IP addresses and not overloading the radio channel, or defining a coverage area associated with a specific class of addresses. To achieve complete transparency between different or unknown network classes (e.g. internet) it is possible to set the subnet mask to 0.0.0.0. The user manual can be downloaded from this page.
ARM radio modems require an external 10-30 V power supply.
If this power supply is not available directly, an intermediate transformer should be used to match the correct voltage to the product.
The LoRaWAN gateway is the main element of a LoRaWAN IoT structure.
Indeed, the gateway generates the LoRaWAN network to the sensors that are registered to it.
Therefore, it is important to follow a series of recommendations in order to maximise the quality and performance of the LoRaWAN network:
1. Install the gateway on a high point and/or move the antenna to a high point; the objective being to obtain the most vertical link possible between the gateway antenna and the sensors attached to it
2. Avoid contact and proximity to metal parts in the vicinity of the antenna
3. Perform network coverage tests with the ACW/LW8-TST tester to validate the location of the IoT sensor installation
4. Ensure that the gateway is powered according to the user manual and that the voltage is stable
LoRaWAN gateways may require a subscription linked to the network core used.
In fact, every LoRaWAN gateway has a network server, either integrated or remote, depending on the customer's needs. Some are free, others are not, and they all have specific disadvantages and advantages.
On the other hand, the connectivity of sensors registered on a proprietary or private LoRaWAN gateway is free.
Antennas and accessories
Testers and LoRa repeaters
Using a network tester is essential for any application: indeed, making sure that the sensor will be installed in a covered area is necessary, otherwise the data measured by the sensor will not be transmitted to an IoT platform for example.
The ATIM network tester is available in LoRaWAN or Sigfox versions. It facilitates the installation of IoT sensors thanks to a simple push button and a colour scale.
0. Register the tester on a Sigfox or LoRaWAN network
1. Press the button
2. Wait several seconds
3. Read the colour displayed by the LED
4. Refer to the colour scale to see the quality of the measured network
LoRa repeaters help densify the converage especially indoor and for water metering use cases.
ATIM developped a LoRa/LoRaWAN repeater that is able to repeat the LoRaWAN signal to any ATIM sensors through a LoRa proprietary link.
You "just" need a 10-30 Vdc power supply for the repeater and set the ATIM sensors that you want their messages to be repeated to be configured in the Repeater Compatibility Mode (available on through the configurator).