Reliable Connectivity to Keep Critical Testing Up and Running
Daimler AG was a German automotive manufacturer who is now officially part of Mercedes-Benz, known for its premium brand cars, trucks and buses. Manufacturing quality products is a core value of the Daimler brands. Daimler customers expect their automobiles to be of very high quality and perform flawlessly.
An important part of the Daimler manufacturing process is the configuring and testing of the electronics that are used to operate a Mercedes-Benz. There are 70-100 electronic control units (ECU) in an automobile, which operate features such as brakes, lights, locks, entertainment system, etc. Daimler has created the Vehicle Diagnostics System (VDS) to coordinate the production process of commissioning and testing all the control units that are added to a car. Daimler uses HiveMQ as the core infrastructure service for VDS to manage the information flow between the test devices on the factory floor and the server-side enterprise IT systems.
Nonstop Manufacturing Process Requires Reliable Software Infrastructure
The Vehicle Diagnostics Systems (VDS) is a critical part of the manufacturing process. If the VDS goes down for more than 10 minutes, the manufacturing line may stop. This is because the VDS fulfills some core functionality in the manufacturing process for E/E components, such as calibrating sensors controlled by an ECU, flashing new firmware, personalizing the key to the car and testing to make sure each ECU works properly. The VDS also generates the test documentation required for the regulatory requirements of the destination country for the vehicle.
Each instance of the VDS includes multiple test devices on the factory floor that are connected with a HiveMQ broker located in the factory. On the server-side, a series of microservices connect as MQTT clients with the HiveMQ broker. These microservices act as front-ends to various information databases and enterprise IT systems that are required to fulfill the VDS commissioning and testing of the automobile.
The VDS has been rolled out in 24 factories around the world. There are 10,000 test devices that connect to the VDS and send 166 messages/second, for a total of nearly 470 million messages/month.
HiveMQ Ensures Reliable Messaging to and from Factory Floor
Daimler selected HiveMQ and MQTT since they needed a reliable message platform to operate in their factories. As mentioned, if the VDS goes down for more than 10 minutes then the assembly line may stop. However, the test device will move around the factory floor and could sometimes lose the network connection. Network access is not always guaranteed on the factory floor since network stability can be an issue and there may be some blind spots in the factory. Daimler saw the benefits of MQTT pub/sub protocol and Quality of Services levels to ensure a test device continues to behave properly if the network connection is dropped and reconnected.
MQTT and HiveMQ also had the advantage that it was a simple protocol with minimal overhead so it was a fast, efficient and easy way to share information between the factory floor and the enterprise IT systems. Daimler considered AMQP and OPC-UA but found these were too complicated and heavyweight for their requirements. In addition, unlike HTTP, MQTT also allows for broadcast messages which is useful when the VDS needs to communicate with all the test devices.
A Reliable Partner Providing Enterprise Support and Maintenance
When looking for a MQTT broker, Daimler considered solutions such as Mosquitto or RabbitMQ. They selected HiveMQ due to the professional enterprise support and maintenance provided by HiveMQ.
“We wanted a solution that was maintained, tested and supported by a company,” explains Jochen Vajda, Chief Architect VDS. “The team at HiveMQ have impressed us since the start. They are very responsive to our questions and requirements and have delivered a high-quality product.”
HiveMQ has been running in the Daimler VDS for 4 years. They have been very satisfied with reliability and stability of the HiveMQ platform.
“HiveMQ has delivered the stability and reliability that we required for our system,” explains Marius Hertfelder, VDS Operations. “We have been running the VDS using HiveMQ for 4 years and the HiveMQ broker has not gone down. It is rock solid, completely reliable. When we do have to restart the broker, it is a very fast process so our downtime is minimal. This is very important since we can’t stop the factory assembly line.”