Contactless point switching (THE BSV SYSTEM)

This system of contactless point switching and passing vehicle identification guarantees reliable short-range and safe data-transfer between a unit on a vehicle and a receiving device (gate of depot, ID point). Length of the message is typically 36 bits and range is from 80 cm to 200 cm (when the vehicle meets the EMC norms) based on the induction method in the 115 – 130 kHz band.

The communication utilizes magnetic field created by the transmitting coil located on the bottom of the vehicle with direction to the rail and the signal is received by the coil fixed between rails or the transmitter is on a collector and receiver is mounted on the trolley.  Both generations work in a free band according to general license GL-30/R/2000 released by ČTÚ 21.11.2000 as 502500/2000-613 with the speed 1200 bits/s (AM) or 4800 bits/s (FM). The safety is by using CRC-12 or CRC-16. One data frame is transmitted in cca 15 ms (4800 bits/s).

This system has been successfully implemented in several variations in Lyon (France), Athens (Greece), Bendigo (Australia) and tested in Milan (Italy) and also in CR in Ostrava and Brno.

•  High velocity of the vehicle passing by: up to 80 km/h (depends on the size of the receiving coil)
• Bi-directional data transfer.
• Passing tram is always detected and identified without the risk of cross-talks to other trail.
•  Capability of transferring additional information (cooperation with board informatics):
• Vehicle number
• Destination of vehicle
• Driver ID
• Vehicle preference on crossroads
• An easy substitution of present system of point switching
• Two button selection – direction “straight on” – “turn”
• one-button selection – change actual state
• Three-button selection “straight” – “left” – “right”
• Can be controlled by a board computer
• Automatic switching
• Careless system
• Low cost and easy installation

Common parameters of contactless point switching

• synchronous data transfer in band 115 kHz to 130 kHz
• ASK modulation with 1200 bits/s or FSK 4800 bit/s
• designed according to General license ČTU
• meets the norms ČSN EN 50155, ČSN 34 1500 and ČSN 34 1510
• power supply from 18V to 36V (on demand can be changed)
• sensitive receiver up to the distance 4 m
• temperature range from -25°C to +70°C (BST-TR includes heating)

The system can be connected to:

•  monitoring system at depot gate – can monitor incoming and outcoming vehicles.
• When part of radio monitoring, can specify real position
• Can support crossroad priority
• Control of one-rail section

• car unit for point switching prepared to be mounted on the driver board or under it. The units that can handle control tasks are BSV-CU, BSV-KB or announcer units EPIS 2.45UIR or NMR.
• transmitting vehicle units and induction cils BSV-TR transmits data
• receivers at points -  receiving induction coils BSV-RC receive and decode data and transfer them to control unit BSV-PU over RS 485 or current loop. BSV-PU evaluate data and send order to switch the point.
• control boxes of trolleybus switches
• system testers

Contactless point switching at a terminus