Lorawan

LoraWAN is a low power wireless technology, ideal for enabling the Internet of Things.

Advantages of low power consumption are that sensors can work for long periods of time, without needing new batteries.

LoraWAN is great for sending small amounts of sensor data, over long distances.

Wireless sensors use Lora to transmit the collected data to a receiving device, called a Gateway.

The Gateway puts the data onto the Internet Cloud.

Once data is in the cloud, it can be used for monitoring, and even for machines to make ‘Smart decisions’, without the need for human interaction.

     

    Creating a ‘Smart Generator’ using LoraWAN

    Smart Generator – This section of the article explains how a marine generator works, and how it could be improved by adding LoraWAN IOT (Internet Of Things) as a smart ships generator.

    The first part of this section explains how a marine ships generator works, and how to service and test it.

    The section will also look at ways that traditional ships generators can be converted into a smart ships generator, by adding LoraWAN IOT connectivity.

    How Does a Marine or land Generator Work?

    How a marine generator works is something I (@acraigmiles) taught to students at South Shields Marine School many times.

    Inside the generator casing the shaft is connected to a Rotor.

    Attached to the Rotor are electromagnetic Poles.

    The Poles are supplied with DC (Direct Current) electricity, and act as electro-magnets.

    Theory states that electricity can be generated by moving a magnet through a coil of wire.

    This is why the Poles attached to the rotor, are turned into electro magnets.

    As the rotor, and hence the poles rotate, they are surrounded by large coils of wire.

    The large coils of wire that surround the poles is called the Stator.

    The Stator coil in a marine generator, consists of three sets of copper wire coils.

    There are three sets because the generator is a three-phase generator.

    The three coils are connected in a star configuration as shown on the screen.

    Each of the phase connections, which I have labelled ‘phase 1’, ‘phase 2’, ‘phase 3’, are connected to the generator ‘Bus Bar’.

    The Bus Bar is the output connection from the generator, which connects to the ships electrical system.

    Generator Exciter

    I mentioned earlier that the poles which are attached to the generators rotor, are supplied with DC (Direct Current).

    The device that generates the DC voltage is called an Exciter.

    The Exciter is attached to the same rotating shaft as the main generator (which is driven by the Prime Mover).

    The difference with the Exciter compared with the main generator, is that the poles are fixed & do not rotate with the rotor.

    Instead the rotor, which contains coils of wire, rotates between the poles.

    Therefore like the main generator, the exciter produces electricity.

    The poles in the Exciter differ slightly from those in the generator.

    The difference is that they retain magnetism, even when the generator is not being used.

    Without this residual magnetism, the generator would not be able to start.

    This is because there would be no magnetic field for the coil of wire (in the stator) to move through.

    Therefore no electricity generated.

    Just like the main generator, the Exciter produces AC, or Alternating Current.

    Therefore to produce the DC needed to supply the generator poles, the AC needs to be connected to DC.

    This is done using a rectifier circuit, which is incorporated into the Exciter.

    A rectifier circuit uses diodes to chop off half of the alternating current, so that only DC is produced at the rectifier circuits output.

    This DC is then fed via wires, into the Poles of the main generator, creating magnetism in the Poles.

    If we didn’t change the original AC produced by the Exciter, into DC, then there would not be a stable magnetic field produced in the generator Poles.

    Fault Finding

    If the generator has been idle for a period of time, and you try to start it, it may not work.

    This is due to the loss of magnetism in the Exciter Poles.

    The Poles are designed to maintain a residual magnetism, even when the generator is off.

    This magnetism can however ‘leak away’.

    This happens over a period of time, due to the fact that the Exciter is encased in a metal casing, which can absorb the magnetism.

    If the generator will not start, and it has not been used for a while, this could be the generator starting problem.

    The solution is to put the lost magnetism, back into the Exciter Poles.

    This is done by what is known as ‘field flashing’.

    You can field flash the Exciter Poles by attaching a battery to the Poles wiring connections, for a short period of time.

    This will re-magnetise the Poles, and hopefully allow the generator to start.

    Generator Maintenance Testing

    A marine generator is both mechanical & electrical.

    Mechanical Checks

    Include bearing lubrication, and wear measurements, using Feeler Guages.

    Electrical checks are mainly focused on the continuity & Insulation resistance values of the generator Stator.

    Continuity Checks

    As previously stated the three coil windings in a marine generator Stator are connected at one end, to form a Star connection.

    Continuity checks test that the coils are not broken, and have a low electrical resistance, from one end of the coil to the other end.

    The only slight problem you may face is that the ‘Star Point’, which is the point at which the three coils are connected together, is not accessible, on your generator.

    This is because the Star Point is often buried in the Stator windings.

    If this is the case, what you need to do is measure the continuity through two sets of windings at a time.

    This is done via the three Bus Bars, using a low range Ohmmeter.

    The resistance should be low, and very similar, between the different coil combinations tested.

    Insulation Resistance Checks

    The three separate coils of wire in the three-phase generator Stator should have a high resistance between them.

    If there was no or little resistance between the coils, then a short circuit would occur, and the generator would not run.

    An insulation resistance meter tests the windings resistance under realistic working conditions, by supplying a high voltage to the coils.

    For a 440 Volt marine generator, you would normally set the insulation meter to double its normal operating voltage.

    Insulation testers typically offer 250, 500 & 1000 Volts ranges.

    Therefore for a 440 Volt marine generator you would test at 1000 Volts.

    If you are regularly testing, you may wish to reduce the meter setting to 500 Volts, so not to unduly put stress on the Stator winding’s.

    The minimum insulation resistance figure under SOLAS regulations is 0.5 Mega Ohms.

    Though really you would not want to see anything below 2 Mega Ohms in a healthy marine generator Stator.

    Smart Ships Generator

    So hopefully now you understand how a traditional ships generator works, and its now time to consider how we can improve it.

    We can help you integrate LoraWAN and other LPWAN wireless connectivity into your existing marine and factory generators.

    We can offer onsite bespoke electrical engineering training & at your site, or at ours.

    Our trainer is Craig , who has lots of experience in training electrical maintenance employees and students.

    Phone: (01522) 740818

      LoraWAN Advantages For Industrial Internet Of Things – IIOT

      LoraWAN advantages for the Internet of Things, or IOT, are discussed in this article.

      LoraWAN is a low data rate, low power, long distance wireless technology.

      The ‘Lora’ part of the name, stands for ‘Long Range’.

      LoraWAN is designed for Internet of Things (IoT) uses.

      LoRa technology offers bi-directional communication, end-to-end security, mobility and localisation options.

      LoRa typically operates within license-free ISM (Industrial, Scientific, Medical) radio frequency bands located below 1 Gigahertz (GHz).

      Operating in the ISM frequency bands, allows anyone to build a LoraWAN network, without the cost of Ofcom (in the UK) spectrum operating licences.

      Lora technology provides very long-transmission range, compared with Wifi & Bluetooth etc, while using exceptionally low power consumption.

      There are of course IOT applications that are better suited to other wireless technologies, such as Wifi.

      LoraWAN can only transmit small amounts of data at a time, so is not suitable for streaming video for example.

      LoraWAN Advantages are listed below:

      Long range and deep penetration

      LoraWAN is good at penetrating into buildings, or even underground. Therefore Sensors can be located indoors, outdoors and even underground, and still be able to communicate with the receiving Gateway device.

      Distances of up to 50Km can be achieved in open areas, and up to 10km within a town or city.

      Low Power

      LoraWAN advantages for IOT is offering low data bit rates, which results in low energy consumption.


      Environmental Sensors such as Smart Parking or Soil sensors are designed with Lora technology, to send small amounts of data when required.

      How often the small amounts of data are sent can be designed to be event-driven or at a scheduled time period.

      This enables battery life to last for up to 10 years.

      High Network Capacity

      Lora uses an adaptive data rate and features a multi-channel multi-modem transceiver in the gateway device.

      This allows for simultaneous messages to be received on on multiple channels.

      Therefore a LoRaWAN network has very high capacity and scalability options.

      Open Standard, unlicensed band

      The LoRaWAN specification is supported and maintained by the LoRa Alliance.

      LoraWAN mostly operates in the licence free ISM (Industrial Scientific Medical) bands.

      In Europe the frequency is 868MHz, and 915 in the USA etc.

      Advantages of LoraWAN operating in an ISM band, is that there are no expensive licence fees to be paid to local regulatory bodies (Ofcom in the UK, for example).

      Potential disadvantages of using unlicenced frequency spectrum, is interference from other users.

      Security

      LoRa has AES-128 encryption built-in as standard.

      Ease of Installation

      As Lora connected Sensors consume only tiny amounts of power, they can run from batteries for a number of years. This makes installation simple, as time consuming & expensive cabling isn’t required.

      Smart Factories using LoraWAN

      Condition Monitoring

      Smart factories improve automation and efficiency compared to traditional factories. LoraWAN is one type of LPWAN wireless technology.

      Efficiency is increased both through process decisions being made without human intervention.

      Efficiency is also increased by using sensor data to monitor the condition of machinery, such as three-phase induction motors.

      Monitoring of induction motors, can include vibration sensors, which monitor the condition of the rotor bearings. A worn bearing will cause increased running friction, which can be monitored by attaching external vibration sensors to the motor casing.

      Other conditions that can be monitored on a factory induction motor, are rotor speed, Stator winding temperature, single phasing faults, current drawn and voltage levels.

      Other uses of smart factory monitoring systems, are the monitoring of the production process.

      Smart Factory Buildings

      The factory building that houses the operational machinery, also forms part of smart factories.

      Automated temperature control has been around for years, and is also used in almost every home too. Its called an automatic thermostat!

      Smart buildings can adapt the heating control automatically, by sensing where heat is needed in the factory building.

      For example sensors, can detect if people are working in a particular section of the factory.

      The sensor data is used to only heat the parts of the factory that require it.

      The use of sensors can also be used to switch lighting on or off, depending on actual real-life demand for light, within sections of the factory.

      Smart control of lighting and heating systems within the factory environment, reduces the variable costs of the the business operation.

      Wireless Connectivity Options

      Various wireless technologies can be used for wireless smart factory connectivity.

      The choice will depend on a number of factors such as communication range needed, data rate and bandwidth requirements.

       

      Technologies that can be used include:

      • Bluetooth
      • LoraWAN
      • Zigbee
      • Wifi

       

      Building a DIY LoraWAN Gateway For The Things Network

      What is a LoraWAN Gateway

      A Lorawan Gateway is the device that receives the wireless signals containing data, that has been transmitted (using Lora wireless technology) from the remote sensors (river level monitoring, air quality etc).

      Once the Gateway has received the wirelessly transmitted data, the gateway forwards the data onto the Internet.

      Gateway connection to the Internet can be via a variety of means, such as Wifi, Ethernet, 3G, 4G, 5G etc.

      Building The LoraWAN Gateway

      For beginners to building their own gateway, I would recommend joining, or founding a local Things Network .

      The Lorawan Gateway that I am going to describe here, is designed to operate on the Things Network, however other lora networks can easily be installed.

      The main components that you will need are:-

      1) A Concentrator board from IMST of Germany. The Concentrator board is the wireless communications part of the system, responsible for receiving the wireless data signals, from the remote environmental sensors (Air quality sensors etc).

      2) A small computer to store the software that controls the Concentrator board. We are going to use the UK designed Raspberry PI 3.

      A Micro SD Card, for holding the software used by the Raspberry PI. A small 4 GB card is fine.

      3) A suitable Antenna (or Aerial), with pigtail connecting cable.

      4) A suitable 2 Amp rated power supply, with a micro USB connector.

      5) 7 Female to Female connecting leads, suitable for raspberry PI.

      4) A suitable case, to house the components.

      The first thing I need to make you aware of is the risk of static electricity, to your IMST ic880a Concentrator and Raspberry PI.

      Static can damage the sensitive electronic components, therefore it is advisable to take precautions, such as not touching the board components, and wearing an anti static wrist strap.

      The first thing you need to do is to format the micro SD card, that will be fitted to the raspberry PI, to hold the gateway software.

      The SD card association has a free piece of software, for Windows PC and Mac, to do this. My card was already formatted, so I skipped this step.

      The next step is to burn the actual software that will power your gateway, onto the Raspberry PI.

      To do this, I used https://etcher.io/    

      I first installed Etcher onto my  linux desktop computer. As most people use Windows PC, or Mac, you will need to find a suitable alternative to Etcher.

      I also downloaded the operating system needed to run the Raspberry Pi, which is called Raspbian Stretch Lite , onto my desktop PC.

      Put your micro SD card into your computers micro SD card reader. If your computer (like mine) does not have a card reader, then external USB plug in ones can be purchased cheaply (I got mine from my local Asda supermarket for £6).

      Fire up Etcher, or whatever card burning software you prefer, and select the copy of Raspbian Stretch Lite , that you previously downloaded to your PC.

      Follow the instructions, and burn the operating system software onto the micro SD card.

      Once you have successfully burned your Raspbian Stretch Lite, onto your SD card, insert it into the Raspberry Pi (the slot is on the underside of the Pi).

      The next thing to do is to connect your Raspberry Pi to a suitable monitor (I used a TV, that had a HDMI connection), and also connect a USB keyboard, power supply, and mouse.

      The power supply should be 5 Volts DC, and Raspberry Pi power supplies are widely available. I used a USB phone charger, with 5 Volts output, and a current rating of 2000mA.

      Boot up your Raspberry Pi (connect the power), and you will see lots of computer code scrolling across your screen (if you have done everything successfully, so far).

      When the Raspberry Pi asks you for a user name and password, use the following default ones (the  bit after the  ‘ : ‘ ).

      Username: Pi

      Password: Raspberry

      After you have successfully logged in, type:

      sudo raspi-config

      Numbered options will now hopefully be on your monitor screen.

      Select [5] Interfacing Options, and then P4 SPI

      Then select [7] Advanced Options , and then [A1] Expand Filesystem.

      You now need to exit the raspi-config utility, either by hitting the ‘CTRL’  and  ‘X’ keys, or by typing sudo reboot

      Next you are going to Configure the locales and time zone.

      Type this in, to set the locales, and follow instruction.

      sudo dpkg-reconfigure locales

      Next, type this in to set time zone.

      sudo dpkg-reconfigure tzdata

      The next stage is to update the raspberry Pi software, do this by typing:

      sudo apt-get update

      Then install any upgrades to the operating system software, by typing sudo apt-get upgrade

      Next we are going to install Git , which is needed to be able to download the Things Network software from Github.

      Type:

      sudo apt-get install git

      The next step is to create a user called TTN (the things network).  This user will eventually replace the default raspberry pi user, which we will delete.

      sudo adduser ttn

      Then:    sudo adduser ttn sudo

      Logout, by typing logout

      Once you have logged out, log back in using the user name and password that you have just set up, when you added a user.

      You can now delete the default Raspberry Pi user, by typing

      sudo userdel -rf pi

      Set the WIFI  SSID and password details, which can be found on the back of your home router / Hub (usually).

      To set the WIFI details type

      sudo nano /etc/wpa_supplicant/wpa_supplicant.conf 

      Once you have typed in the above text, you should see some code on the screen. Add the following to the end of the existing code, making sure that you enter your SSID and password details, in place of the shown text.

      network=

      {
      ssid="The_SSID_of_your_wifi"
      psk="Your_wifi_password"

      }

      Now we are going to clone the installer from Github. This will download the software which runs the gateway, from the Github repository.  Type each of the following three code lines into your Pi, one at a time, hitting the return key after each line of code.

        git clone -b spi https://github.com/ttn-zh/ic880a-gateway.git ~/ic880a-gateway
        cd ~/ic880a-gateway
        sudo ./install.sh spi

      Identifying the Gateway

      The software will give the gateway the default name of ttn-gateway.

      This however may need to be changed, to prevent issues with other Things Network Gateways within wireless range.

      Wiring it Up

      The next step is to connect the Concentrator board, to the Raspberry Pi, and also connect the antenna.

      The components including the antenna should be mounted in a protective box,  and the antenna connected to the Concentrator board.

      It is very important that the Concentrator board is not powered up, with no suitable antenna connected, of damage could occur to the board.

      Once the antenna is connected, then the next step is to connect the Concentrator to the Raspberry Pi.

      Connect using female to female connecting wires, as follows:

      iC880a Concentrator pin Description RPi physical pin
      21 Supply 5V 2
      22 GND 6
      13 Reset 22
      14 SPI CLK 23
      15 MISO 21
      16 MOSI 19
      17 NSS 24

      IMPORTANT DISCLAIMER:

      It is important that you identify the correct pins, by referring to the manufactures data sheets (Both IMST & Raspberry Pi).

      We accept no liability for loss or damage caused, by following these information only instructions.

      For help, as to which pin is which on the Concentrator and Raspberry Pi boards, why not get in touch.

       

       

      Leave a Reply

      Your email address will not be published. Required fields are marked *