The question remains: Analogue or digital
Signals from wheel sensors can be analogue or digital. Manfred Sommergruber uses the example of the Frauscher RSR110 wheel sensor to explain the respective features.
Openness is the way forward: when developing solutions for the railway sector, this means that information on and about the interface is passed on in a comprehensible and structured manner. This is the only way to make know-how available, which can then be used to optimally identify and meet the requirements of individual projects.
If inductive wheel sensors are developed following this philosophy, then this offers a whole range of specific benefits. Thus, the sensor signal is made available unchanged and directly via an open interface, whereby implementation and evaluation can be completely customised. Direct integration also ensures the maximum level of detail during the evaluation. Since no specific evaluation unit is needed, the need for hardware components, space and energy consumption and the associated costs are reduced to a minimum.“The conviction that a wheel sensor with an open analogue interface can offer significant benefits to system integrators and operators, was the driving force behind the development of the RSR110. This wheel sensor combines robustness and reliability and is the first one from our portfolio that is available without an evaluation unit. Our customers can use the sensor signal as required by the respective application,” says Manfred Sommergruber, Technical Sales Manager at Frauscher, explaining the history behind the product.
Soon after its launch, this wheel sensor was installed in a wide range of applications – and new ones continue to be added. For example, Prosoft now uses the RSR110 as a standard component in its RFID systems. “Based on the open interface of this sensor, we can fully evaluate the signal according to our requirements,” says Martin Novak, CEO Prosoft Süd Consulting GmbH. “The high level of accuracy demonstrated by this device and the flexible integration options were key reasons in our decision to use the RSR110 today as a standard component in our systems.”
Wheel sensors with an open interface are used for individual evaluations.
Analogue or digital?
True too of open interfaces is that, in comparison to an analogue interface, the digital version offers benefits in particular with regard to the speedy completion of the integration. Different Frauscher wheel detection systems use special evaluation units here. The resulting digitalised signals go through a pre-evaluation stage, which makes it possible for the data to be further processed quickly.
“After having implemented the RSR110 into several projects, we received positive feedback from various markets. At the same time, however, we discovered as we talked to customers that some do not actually need such accurate information as the analogue signal provides. Instead, a pre-evaluated digital signal including digital interface would have been sufficient in some instances,” says Manfred Sommergruber. “So, we decided to develop a Wheel Sensor Signal Converter WSC, which converts the analogue signal into a digital signal and creates the corresponding interface. This not only reduces the outlay for the customer, who now no longer has to deal with the conversion themselves. It has also led to an even quicker and simpler integration into higher-level systems.”
Flexibility is key
In principle, the same information can be provided via analogue and digital interfaces. They differ in that the pre-evaluation for the signal conversion to some degree limits the possible level of detail of further evaluations, unlike when directly inputting the analogue signal into higher-level systems.
“With the RSR110 and WSC, however, we can always offer our customers exactly those components that meet the requirements of the individual project,” summarises Manfred Sommergruber, giving an example of a project where both approaches were applied: “The feedback from one customer was that he is already using the RSR110 together with the WSC board to feed the sensor information into his system via the digital interface.
This in turn activates various monitoring systems. However, one specific installation required the exact wheel positions to be evaluated. This requirement was met by directly feeding in the analogue signal, which simply resulted in other RSR110 sensors with no WSC board having to be implemented. It was therefore possible to successfully fulfil two requirements using just the one product.”
The signal can be used directly from the sensor or can be digitalised first via the WSC for simpler integration.
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