The Swiss Federal Institute of Metrology (METAS) is currently updating around three hundred hydrological measuring stations in Switzerland to the latest state of the art. One of the stations records the outflow of the Great Aletsch Glacier. To obtain reliable measurements despite the difficult environmental conditions, METAS relies on a control system from B&R.
The Federal Office for the Environment (FOEN) operates 314 hydrological metering stations throughout Switzerland to monitor the its water resources. The metering stations conduct quantitative and qualitative measurements in Switzerland's rivers, lakes, streams and groundwater. The Swiss Federal Institute of Metrology (METAS) is responsible for the instrumentation and technical administration of the network in which the stations are integrated. The sensors and data loggers at the metering stations had been in operation for about 30 years when METAS began to gradually renew the instrumentation.
"We knew that we wanted to use standard automation solutions at the stations," explains Daniel Lussi, head of the METAS metering station renewal project. "This enables us to react to the different local conditions of the individual metering stations and easily integrate new technologies in the future. The concept is not only suitable for hydrological metering stations, but can also be easily applied to other environmental metering stations.
The modernized metering station on the Great Aletsch Glacier is located near Massa Blatten and was put into operation at the end of September 2017. With a length of about 23 kilometers, the Great Aletsch Glacier is the longest glacier in the Alps.
"A glacier is not a body of water, so we don't measure it," explains Lussi, "but what FOEN and METAS are responsible for is monitoring what is called glacial discharge. At Massa Blatten we measure the volume and temperature of the melt water. Other metering stations also record other parameters, such as turbidity." Among other things, FOEN uses these parameters to learn more about the consequences of global warming.
The Massa Blatten metering station can only be reached via the cable car operated by the EnAlpin AG power station. "At a location like that, it's difficult to perform maintenance on short notice, so all the components must be especially reliable," says Lussi, explaining one of the fundamental requirements for the control system. Another important criteria in the selection of a provider was that the system be OPC UA capable and able to communicate with the existing SCADA system and other applications, such as the historical database and the information, alarm and reporting systems.
B&R's modular and integrated control solution prevailed over multiple competitors in the selection process for the metering stations. At the time, in 2015, B&R stood out among the competition through its early implementation of OPC UA. B&R also offered an impressive number of I/O modules and software libraries in its Automation Studio development environment.
"B&R's Automation Studio provides a huge variety of functions and libraries. This makes it very easy to do things like integrate the HART protocol into a B&R solution. We have many HART bus devices in the field, which not only need to be read, but also configured. With the DTM (device type manager) from the HART bus devices integrated in Automation Studio, we save ourselves a lot of implementation effort," says Lussi. "B&R was also able to offer us the component traceability that is so important for us."
Due to the often harsh on-site conditions, all devices had to be robust and reliable and suitable for both high and low temperatures. B&R technology also meets this requirement. In the end, B&R was awarded the contract for the control solution including an X20 controller, bus controllers, I/O modules and T30 operator panels for entering parameters in the field.
Communication within the METAS network is based on the classical automation pyramid: The measured values are recorded by the sensors and communicated to the controller. In turn, the controller communicates via Ethernet and OPC UA with the higher-level SCADA system that METAS uses for control, parameterization and monitoring of all metering systems. The data is also available to all applications in the METAS network via OPC UA.
"The measuring station in Massa Blatten has no mobile phone reception and there is no landline available," explains Lussi. The main installation was therefore positioned in a power plant cavern 350 meters away. From the main control cabinet in the cavern, a fiber optic cable leads to a bus controller in the metering station itself. Data is sent from the remote station to the controller in real time via POWERLINK.
"Rather than have a separate configuration for each metering station, we're able to cover most systems with a selection of standard configurations. This keeps the effort of integrating new metering stations into the METAS network to an absolute minimum – it only takes a few minutes," says Lussi. If none of the standard configurations fit, as was the case in Massa Blatten, creating a new configuration doesn't add much effort either.
"Thanks to the design of B&R's control technology and and Automation Studio, it doesn't take us more than an hour," reports Lussi. The ability to implement different hardware configurations in a single project is a major advantage that B&R technology and Automation Studio offers over competitors. For example, all metering stations use the same IP addresses for the HMI panels and the controllers. "This simplifies installation considerably," notes Lussi. "Using B&R technology has not only increased our flexibility, but also greatly improved the reliability of our metering systems.
Head of Metering Networks, METAS
"Working with B&R has been a very positive experience. Direct contact with B&R's technical support is fast and uncomplicated. This was very important for the successful implementation of our project."