Counting Head Control

The Counting Head Control (CHC) feature enhances system availability by continuously monitoring the condition of counting heads (wheel sensors) and their designated track sections. CHC automatically detects and corrects external interferences that could affect track section occupancy data.

This feature ensures that wheel sensors are only activated when a wheel passes over them. In cases where a sensor is damped without an actual train being present in the track sections adjacent to it, the system keeps the track sections reported as clear. By placing the affected sensor in a standby mode, any false occupancy reports are effectively suppressed, ensuring consistent and reliable track status information. If the sensor is subsequently traversed by a wheel, the system immediately switches back to active and resumes reporting at a SIL4 safety level.

The CHC feature functions as an intelligent layer within the axle counting system. Once configured, it oversees connected track sections and ensures that the predefined control logic is applied consistently, so counting heads are activated only when traversed by a wheel.

The resulting occupancy or fault information is provided via the Advanced Evaluation Board AEB. When a counting head is damped but no actual wheel passage is detected, the CHC logic keeps the associated track section reported as clear. In case of external interferences, the CHC flags the affected sensors and initiates corrective actions to automatically restore normal operation without manual intervention.