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The wheel axis passage sensor for train mobile units (type DPD)

The wheel axis passage sensor for train mobile units (type DPD)

General description of the wheel sensors of type DPD

The wheel sensors of type DPD have been developed for use in the devices and systems of railway and metro automation for the determination of the moment when wheel axis passes above the center of the sensor.

Advantages

- High stability of determination of the moment when wheel axis passes above the sensor center for any of railway vehicles.
- Noise immunity to any external electric and magnetic field, including insensitivity to the traction currents and pulse noises, caused by spark discharges. High resistance to the vibration of the rails.
- Independence of the sensor output signal amplitude and sensitivity area on the train velocity.
- Wide nomenclature of produced sensors with wide range of performed functions is implemented within a single interface. This allows for implementation of the most various tasks of control of rolling-stock parameters within a single type message-exchange and signal-processing board.
- Simple fixation on rails, without cutting, welding and drillings routines.

Application

- Position detection of wheel axis of a rolling-stock with respect to the sensor position (used for the synchronization of the measurement equipment).
- Count of axes for a rolling-stock.
- Determination of rolling-stock parameters (presence of train within the control area, direction of motion, speed).
- Vehicle recognition by the measured interaxial spacing.

Types of produced sensors

Within the series are presented: DPD-01 (differential),  DPD-02 and DPD-03.
– Wheel sensors of  type DPD-01 are sensors, which have a bidirectional voltage pulse  output signal in form of two half-waves. The polarity change occurs in the moment when the wheel axis passes above the sensor center.
– Wheel sensors of  type DPD-02 are sensors, which have two type output signals: current pulse, produced when the wheel axis passes above the sensor center, and an analog signal in form of two half-waves.
– Wheel sensors of  type DPD-03 are sensors, which have two signal outputs. Each signal is generated as a decreasing half-wave when the wheel axis passes above the sensor.  These signals are shifted in time. When the wheel axis is above the sensor center the signal on both outputs is equalized. In absence of the wheel the signal on both outputs is constant and has its maximal value.