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Smartio® – the new smart remote I/O system

Smartio® - modular system architecturezoom

Smartio® – the clue is in the name. Selectron uses this name to describe its new decentralised, standardised input/output system for signal conditioning of the vehicle controller. What it means is simple connection as well as optimum wiring of the usual sensors and actuators in the rail vehicle. This article describes the targets, motivation and basic concepts of the new system.

"Smart" of course means something that is astute, ingenious, intelligent, clever, elegant, adept, etc. But what is so special about these modules? In the final analysis, of course, digital/analog sensors and actuators are connected to the modules and are thus converted for serial data communication with a higher-level vehicle controller. We are familiar with these network concepts from the decentralised instrumentation and control systems with CANopen or MVB vehicle buses, which have been established for years. 

The trick with the new modules concerns their ingenious design. Here, particular emphasis has been placed on practical handling as well as implementing a flexible and cost-saving wiring technique. The first objective of the development was to reduce further the hardware procurement costs for users. The second objective was to generate a significant savings potential in terms of expenditure on wiring. The handling and connection techniques had to be optimised for this.


Here is an extract from the basic requirements from the Smartio® market specifications:

  • Saving installation space
  • Unrestricted mounting orientation
  • Scarcely any limits on expansion options
  • Can be extended subsequently without problems (including in the long term)
  • Simplified connection technique
  • Can be used centrally in the control cabinet or distributed throughout the train
  • High flexibility
  • Clear labelling possibilities
  •  Various network protocols – improved application possibilities
  • Can be used on currently available Selectron CPUs
  • Integration to the Selectron software landscape


Implementation certainly presented us with a challenge. It quickly became clear that one or two design tweaks alone would not lead to success. Only the sum total of many detailed optimisations was able to produce the desired success. For this reason, technical discussions were held at an early stage with many expert users; current solutions were analysed with regard to improvement potential and new implementation concepts were discussed.

The most unusual feature of the new module concerns the concept of the "electronic connection terminal block". This involves combining classic modular terminal block technology (terminal level) with electronic signal preprocessing in one housing (I/O level). All features of potential distribution are retained in this case. This concept creates significant wiring advantages. It enables the control cabinet builder to save a significant amount of time, effort and costs. Furthermore, the emphasis is on simple handling. When an input/output island is needed, it is specifically assembled from individual components ("just-enough" approach) and connected together in a stable mechanical method. It is extremely easy to install and remove the components. The mechanical release function required for this can be accessed on the front at any time. The logistics handling capabilities, such as front labelling with serial number and revision status, electronic scanning in the packing in the goods receipt area or when installed on the vehicle, are just some of the features that permit a smoothly running logistics structure.

The modules comply with current railway standards (e.g. EN 50155, IEC 60571, EN 45545 etc.) with regard to shock, vibration, temperature (-40°C .. +70°C) and EMC. SIL 1 applications can be achieved for selected modules.

The aforementioned objectives have all been met from our perspective. The new modules are shortly about to be launched on the market. We are eagerly anticipating confirmation from future users that they also appreciate the new features. Are you interested? We will provide a description of the technical details in the next newsletter.


Subject to technical changes and amendments to technical specifications at any time.

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