During the product portfolio development, RT-RK collected extensive experience in all IoT areas. Based on that expertise, Endress+Hauser, the leading supplier of products, solutions and services for industrial process measurement and automation, selected RT-RK for the development of SGC200, their Industrial IoT Gateway. The development started from a concept and resulted in a fully qualified product.
To develop a complex and robust product like SGC200, a wide range of skills and experience is required. This case study focuses on system software. Click here for more information about the related hardware and mechanical expertise of this project.
The key points of the project
The software of the product itself was developed based on the OBLO IoT Gateway core. The top-level software diagram is shown on the diagram below.
The platform is an ARM based 3G/4G platform, running a Linux based framework. The C++ OBLO core was ported to the target platform, and then extended with application specific modules that carry additional functionalities.
The system manager handles the system boot procedure, the firmware upgrade procedure, error logging and diagnostics. In failure modes the device stores the error logs, and uploads them to the server on demand, thus easing the diagnostics process.
The targeted use case of the product envisioned prolonged operation on batteries, therefore the power management had to be implemented throughout the entire gateway software, implementing several power management strategies. The data is sent via cellular network. The energy efficiency is achieved by utilization of various power sleep modes, as well as adaptation of data transfer schedule.
The cloud connector module implements the cloud connectivity and ensures bidirectional flow of data and commands. It uses secure technologies defined by the cloud API. The data transfer is dictated by the selected power limitations. The component implements an advanced store&forward mechanism that prevents the data loss even in case of operational disruptions.
Being an industrial application, the sensor connectivity relies on additional security build on top of the Bluetooth protocol. The component talks to Bluetooth sensors, interprets their data, and integrates them into the Core middleware.
The commissioning of the device is done using mobile apps, via an additional Bluetooth connection preserved for this purpose. It implements E+H’s protocol for communication with mobile clients and allows the monitoring and configuration of the device in the field.
Beside the device firmware, the additional supporting tools were developed:
- the factory test application adapted to the actual test bench in the factory
- a programming tool used on the production line, for:
- downloading the test firmware (Factory Test Application – FTA)
- after successfully testing the device on the test bench, to download the final, golden firmware for the product
- test applications used during the certification and qualification processes
The product is still being supported and maintained.
The users expect a high level of robustness of industrial IoT gateways, in all aspects. Starting from a mature Core as a base enabled reaching the desired stability and reduced the time-to-market. The porting and customization activities were a nice fit for the skilled embedded Linux team.