Metering systems with smart meters are being used more and more across Europe and across industries. Accordingly, the demand for suitable devices to read and transmit the data remotely by radio is growing. For transmission via LoRaWAN, an optical reader is now on the market for the first time.
Modern metering systems with smart meters for electricity, gas, heat and water are becoming increasingly important. Within a few years they will have replaced the old analogue systems. The reasons are the technological advantages and various laws and regulations, such as the EU Energy Efficiency Directive or the German Metering Point Operation Act. In addition to municipal utilities and housing companies, commercial and industrial gas users are also recording their measured values continuously and electronically more and more often. This allows them to analyse consumption data and usage times, to display and control consumption flows transparently, and, for example, to detect potential hazards in industrial plants early on. Accordingly, the demand for suitable devices to read and transmit the data remotely by radio is growing.
EU Energy Efficiency Directive
Under the revised EU Energy Efficiency Directive (EED), member states are to promote more efficient use of energy. The EED requires a revision of the German Heating Costs Ordinance with regard to remotely readable heat cost allocators and sub-annual consumption information for better climate protection: from October this year, tenants and residents must be informed of their consumption twice a year, and from 2022 even monthly. From next year onwards, only remotely readable meters and allocators should therefore be installed wherever possible.
Making gas readings accessible
Companies that use modern metering systems have various options for making gas readings available to the responsible grid operator or to the customer. To transmit values in building automation, they often use the S0 hardware interface, which transmits consumption quantities by wired pulse. Alternatively, the wired fieldbus for data acquisition, the Meter-Bus (M-Bus for short), or its wireless counterpart, wireless M-Bus, are used. A fieldbus connects devices such as sensors and actuators for communication with an automation device. The disadvantage: if a company wants to use the interface, this can involve considerable effort, depending on which meter model is in use. In addition, the grid operator can block its use, in which case the interface is not accessible to the company. Nor do the interfaces mentioned here make it possible to read battery-powered meters in short cycles, because the effort would be very high due to frequent battery changes.
The optical interface delivers valuable data
Modern meters today usually come with an optical customer interface. Until now, this has been used for parameterisation when a device is commissioned, or to diagnose a fault in the event of a malfunction. Special maintenance programs are used for this by connecting an infrared receiver to a laptop via USB. The optical interface is the simplest and most cost-effective way of transmitting values from gas meters. The advantages are obvious: no cabling is needed, nor are large additional devices with their own power supply and mobile connection. In addition, readings can be obtained that support grid planning, make grids more transparent or help with balancing. Industrial plants can also be monitored on the basis of the data obtained. The energy industry can use optical readers to read battery-powered metering systems without mains power cost-effectively, permanently or temporarily, for example small regulating stations without mains voltage on site, using existing quantometers or uncalibrated meters.
German Metering Point Operation Act
The German Metering Point Operation Act (MsbG) came into force more than three years ago. With it, the legislator obliged metering point operators to use smart metering technology for electricity, gas, water and heat across the board.
The data from the optical interfaces also helps to maintain, control and service plants and grids: operators detect possible malfunctions and faults in advance and can eliminate them as quickly as possible. This reduces the consequential damage caused by consumption values that cannot be billed. And for grid operators, the optical interface provides additional readings and data for analysis, so they can monitor gas temperature and gas pressure, for example, and optimise their grids.
LoRaWAN: licence-free radio
A still comparatively new technology that allows utilities and companies to read gas readings optically and forward them is a Long Range Wide Area Network, LoRaWAN for short (Fig. 1). In parallel with the growing number of smart metering systems in gas and electricity supply in the German-speaking region, and the ever-increasing penetration of this licence-free radio standard, the demand for suitable readers for the optical interfaces of meters is also rising.
LoRaWAN
The abbreviation stands for Long Range Wide Area Network. The licence-free radio standard transmits measurement and sensor data with little energy, even over long distances, and offers excellent building penetration. LoRaWAN sensors are also simple in design, which makes them inexpensive and flexible to use, with long battery lives of up to five years. The possible applications go far beyond energy saving and include smart offices, smart buildings and even smart cities. A building's own IoT is particularly worthwhile for larger residential buildings, but also for complexes such as office buildings or shopping centres, where a sensor-based IoT can be used to build energy-efficient facility management. And thanks to the long range, municipalities can use LoRaWAN to introduce intelligent, sensor-based street lighting, for example.
Reading optical interfaces via LoRaWAN
Since the beginning of last year, the first sensor has been on the market that can continuously capture values via the optical interfaces of modern meters and transmit them via LoRaWAN. The reader, named "KLAX", is a communication module with an optical head that attaches directly to the meter's optical interface with its integrated magnet. Depending on the meter type, KLAX either fetches the required readings and transmits them to the gateway or instructs the meter to transmit them. The product enables energy utilities and housing companies to offer value-added services based on the available readings, because the data is available in the back end shortly afterwards and can be processed further. The IoT company Alpha-Omega Technology developed and manufactured the module together with Comtac and Zenner IoT Solutions. Operating KLAX requires a LoRaWAN infrastructure that receives, forwards and decrypts the transmitted data packets. After KLAX had been used successfully in the electricity sector, a need for a solution for capturing readings in the gas sector quickly became apparent, and the product was developed further accordingly. Only six months after the product launch, several grid operators that run gas grids in addition to electricity grids contacted us. They suggested that we enable KLAX to communicate with electronic volume converters or peak-load indicators (data loggers) as well. If these are not operated as interval metering (RLM), they usually run on batteries. KLAX therefore offers a cost-effective way of reading values such as operating volume, standard volume, pressure and gas temperature from these devices too. The market for electronic gas meters is divided into devices based on the SML (Smart Message Language) optical interface and those that use the Modbus protocol. KLAX is therefore available with the appropriate firmware for each. The original KLAX is based on SML and is particularly suitable for capturing and transmitting data from electricity meters that use this protocol, typically in apartment buildings or office buildings. The product innovation has already proven itself in practice and reliably delivers consumption values from thousands of electricity meters. The Hamburg Port Authority (HPA), for example, is currently optimising its energy management together with Stromnetz Hamburg (SNH). Using the city's LoRaWAN network and KLAX, more than 300 remotely readable digital electricity metering points are recorded fully automatically every 15 minutes.
Optimising gas grids and monitoring plants
To capture gas values at energy utilities or in industrial companies, the SML KLAX can now read not only the familiar electricity meters but also the electronic volume converters from Feingerätebau Tritschler GmbH. Via the Modbus protocol, the reader now also addresses many other gas meters, such as the Primus 400, Prilog 400 and TME models from RMG Messtechnik GmbH. On delivery, the four registers for operating volume, standard volume, pressure and temperature of RMG's current product line are preset. The Modbus KLAX reaches all meters that use Modbus on the optical interface, and the user can parameterise the device via downlink to the appropriate register addresses. The user can also configure KLAX so that, in addition to the standard values, it monitors the flow rate or transmits daily values, for example, and the measurement and transmission cycles can be changed as well. In combination with a calorific value meter or gas chromatograph and the appropriate recording device for the readings, the optical reader is even able to transmit the gas composition or the calorific value.
This article was published in e|m|w 2|20
By Michael Müller, Senior Project Manager, Alpha-Omega Technology GmbH & Co. KG