iO881A adheres magnetically to the optical interface of the meter

With the certification of three independent manufacturers of smart meter gateways by the German Federal Office for Information Security (BSI) at the beginning of 2020, the rollout of smart meters in Germany has been given a green light.

The installation of so-called smart metering systems, i.e. systems that can communicate with the help of a communication module, is mandatory for electricity customers with an annual consumption of more than 6,000 kWh. In contrast, if consumption falls below this threshold, it is only required to install so-called “modern” electricity meters which feature a display, but not a communication module. They therefore do not provide data for value-added services (visualisation of consumption data, proof of energy efficiency, etc.).

IMST GmbH has accumulated valuable experience in the field of optical read heads with the development of the wireless optical read head Power Control for the RWE product family Smart Home.

Based on this, IMST GmbH now offers with the package iOKE868 for LoRaWAN® a version of a bidirectional optical reading head iO881A that includes the long range wireless communication technology LoRaWAN® on 868 MHz. It can be used to securely transfer consumption data from various meters to the cloud, where value-added services can process the data. The iO881A reading head is intended for both private households and commercial customers.

IMST GmbH has accumulated valuable experience in the field of optical read heads with the development of the wireless optical read head Power Control for the RWE product family Smart Home.

Functional description

The iOKE868 for LoRaWAN® package includes the optical reading head iO881A, an external antenna and a USB cable to connect a battery or USB power supply. Thanks to its LoRaWAN® certification, compatibility with existing LoRaWAN® networks is ensured. If a network is available, no further infrastructure is required to operate the iO881A.

The magnetic reading head iO881A is easy to install and is one of the few radio-based optical reading heads that complies with the size requirements of the IEC62056-21 standard. This ensures that the meter cabinet where the reading head is installed can also be closed. The reading head is supplied with an external antenna including a 2m antenna cable. The antenna, which also adheres magnetically, can be easily installed outside the usually metal control cabinet and thus enables a greater range. Furthermore, due to the 2m long antenna cable, you have greater freedom in the choice of the antenna installation location. This can be a decisive advantage, especially in difficult installation environments, such as basements.

The iO881A reading head “understands” the formats SML and IEC62056-21, which are used by most commercially available meters. Furthermore, not only electricity meters are supported, but all electronic consumption or generation meters (electricity, photovoltaic systems, water, gas, heat, …) that are equipped with a corresponding infrared interface.
It can be connected to a PC/laptop using the USB cable supplied. With the help of the free configuration tool WS-Configurator the following functions are available:

General device information and software update

Output of all OBIS1 key values detected by the reading head, which the respective meter outputs on the infrared interface2

A direct mode that allows unfiltered output of infrared data sets to the USB interface

Easy integration of the reading head into a LoRaWAN® network

Creation of up to 32 OBIS filters from the selection of detected OBIS key values

Creation of up to 32 calendar events (sending of device status, meter reading and transmission) including corresponding repetition rates on a minute, hour, day and week basis or continuous operation

Assignment of the configured OBIS filters to the individual calendar events. The set filters are applied to the counter data records to reduce the data volume accordingly

The iO881A reading head “understands” the formats SML and IEC62056-21, which are used by most commercially available meters.

iO881A. Optical reading head

The iO881A  reading head has a push button and a two-colour LED, as well as a USB interface. Via this interface, the reading head can be powered by a battery pack for standard AA batteries, or by a USB power supply. Thanks to the low current consumption of only 4µA, continuous battery operation for several years is possible3.
The time or date required for calendar operation can be regularly requested by the respective LoRaWAN® network as a calendar event. The read head then automatically and periodically synchronizes itself with the time and date of the LoRaWAN® network. Among other things, this enables readings to be taken on defined dates, such as every 1st or 15th of the month.

The integrated LoRaWAN® protocol stack of the iO881A ensures compliance with the regulatory duty cycle4 requirements, so that the highest possible wireless transmission rate allowed is automatically selected when meter data is continuously collected.
Furthermore, the LoRaWAN® protocol stack uses the so-called ADR5 (Adaptive Data Rate) procedure to optimally regulate the data rate depending on the LoRaWAN® link quality.
The iO881A reading head is LoRaWAN® certified and can therefore be operated in all LoRaWAN® networks. For this purpose, the corresponding keys of the respective LoRaWAN® network must be configured in the reading head using the WS-Configurator. The transmission between the iO881A and the LoRaWAN® network is thus encrypted and authenticated.

The external antenna with the 2 meter long antenna cable of the iO881A is especially helpful. It allows the antenna to be installed outside the control cabinet and thus generally permits the use of a higher wireless data rate compared to an integrated antenna.

Send meter data to the cloud easily and securely with iOKE868 LoRaWAN®

A widely used LoRaWAN® network is that of the provider TheThingsNetwork (TTN). According to TTN, the LoRaWAN® network currently consists of over 16,000 gateways. The use for gateways and end devices is free of charge in this basic version. In addition to the LoRaWAN® network, a cloud platform is needed to process and visualise the corresponding data. Here TagoIO offers a variety of free options for data preparation, visualisation, analysis and alarming in case of critical values.
To operate the iO881A reading head with TTN and TagoIO, a so-called Connector is already stored in TagoIO. On the network side, this already completely maps the reading head iO881A , so that only the Connector of iO881A must be selected as a device here. The Connector also contains a visualisation proposal, a so-called dashboard, and a so-called parser (data interpreter), which interprets the received data on the network side and prepares it for visualization.
Commissioning and visualisation of the consumption data using a PC/laptop or a smart phone is therefore possible in just a few steps. A corresponding manual is part of the package iOKE868 for LoRaWAN®. Additionally, other scripts for other platforms are part of the iOKE868 for LoRaWAN® package. These and the corresponding dashboards for visualisation, can also be adapted and changed according to your own needs.

TagoIO Platform

Another alternative is to use the open source project ChirpStack. This free software package allows you to operate your own LoRaWAN® network. However, this requires a slightly greater effort, so that this alternative may not make that much sense for for individual devices. However, since the ChirpStack is used in many communities or cities in so-called campus networks, IMST GmbH provides a corresponding application manual. A ChirpStack in connection with an Influx database and a grafana visualization has been successfully implemented and operated in Kamp-Lintfort for years.

Grafana data visualization

[1] The measured values, meter readings, consumption data including their units are coded in so-called OBIS (“Object Identification System”) key figures.
[2] Meters can output different OBIS key figures depending on the manufacturer and setting. For further information, please refer to the metering point operator.
[3] The operating time depends on the configuration of the system.
[4] The duty cycle defines a legally required limitation of the transmission time of a device.
[5] In a LoRaWAN® connection, the data rate is reduced accordingly when the connection quality deteriorates.

LoRa Alliance® and LoRaWAN® are marks used under license from the LoRa Alliance.