Access Control with RFID System

Turck's IO-Link RFID system secures high-voltage tests at the Belgian railroad SNCB

To guarantee safe working conditions, companies must reliably ensure that only people with the appropriate training are allowed access to certain areas and facilities. The Belgian railroad company SNCB uses an RFID system from Turck to monitor access to the high-voltage test areas of its central workshop in Mechelen. Trains are maintained, rebuilt and overhauled there. In a new laboratory, SNCB tests the power converters of the trains at 3000 volts.

  • The entrances to SNCB's high-voltage test room can only be opened by authorized employees via RFID tags

  • The K50 LED indicator with sound signal changes to red as soon as the test procedure is active

  • After scanning the RFID tag by the TN-M30-IOL-H1141 in the console, the test procedure can be started

  • Turck IO-Link master TBEN-L5-8IOL takes care of the signal transmission

  • The LED signal lights are connected via Turck’s compact TBEN-S2 I/O module

  • All entrances are secured via Turck's RFID solution so that only authorized persons are granted access

  • Jimmy Volders, Dymotec, Kristof Honee, SNCB, and Danny D'hollander, Turck Multiprox (from left)

"The risks of a 3000 V installation should not be underestimated," says Kristof Honee, in charge of the electronics department at Belgian Railways SNCB's central workshop in Mechelen. "Even when the voltage is switched off, there can still be charge in coils and capacitors. That's why the work must always be done systematically, according to established procedures and by people who are aware of the risks." In Belgium, overhead power lines for trains carry a DC voltage of 3000 volts. Power converters on the trains convert the high voltage into lower voltages for the drives, air conditioning and all other equipment.

Laboratory power supply delivers 3000 volts

"In the new lab, we have three test zones to test the converters after they have been overhauled or repaired," Honee explains. "Many components can be tested at lower voltages, but for the final test, we use a laboratory power supply that can deliver 3000 volts, just like the overhead line." The tests must be conducted according to strictly regulated procedures, with close attention paid to safety risks.

SNCB asked the Belgian systems integrator Dymotec - specialized in industrial electrical installations and automation - to develop a system capable of managing the test procedures while respecting all the required safety aspects and controlling access. Key to this is the management of authorizations and the tracking of all procedures.

RFID system secures access to the test area

At the entrance gate to the test areas in the laboratory, K50 LED signal lights are installed that change color depending on the status of a zone. At each door, as well as at the control panels, there is an RFID reader where operators must have their badge, an RFID data carrier, read to gain access. "Our employees receive training to cover all safety aspects of each type of converter," says Kristof Honee. "Dymotec's system ensures that all safety requirements are met at every step of the testing process."

The RFID readers check who is logging in. The PLC checks to see if that person is authorized to gain access in a particular situation or to start the next step of an operation. Finally, the PLC controls the lab's power supply and ensures that the test setup is turned on only when the situation is safe. Operators must confirm each step so nothing is overlooked.

RFID read/write heads and indicator lamps

Dymotec uses Turck's RFID system for this purpose. The RFID read/write heads read the ID of a badge and transmit it to the PLC via IO-Link. "The RFID system can be implemented quite easily," says Jimmy Volders, project manager at Dymotec. "The RFID readers and the signal lamps are connected to IO-Link masters via IO-Link. These also provide the power supply, so not much cabling is needed."

The TBEN-L5-8IOL IO-Link masters communicate with the PLC via Profinet. Using the IO-Link modules' integrated two-port switch, the masters form a line topology so that only one Profinet line needs to be run from access door to access door, which in turn saves wiring work.

The test areas are equipped with K50 signal ights from Banner Engineering, which are controlled by the PLC to change color. As a result, one light per entrance door is sufficient, unlike traditional stick-type color signal lights. Programming does not have to be limited to selecting a single color. The LEDs can be controlled individually. The control units have been equipped with signal lights with sound function, so the system can also issue acoustic warning signals. 

Thanks to the automation of the test facility, all safety procedures are now implemented effectively - without slowing down operations through manual processes. Full traceability of every action is ensured throughout. 

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