Solid State Block Proving By Axle Counter (Digital)
SSBPAC is a solid state system used for controlling the coordinated movement of the train in the block section working on absolute block working principle. The system has been developed as per RDSO/SPN/175/2005 both for single line working and double line working.
Salient Features:
The SSBPAC (D) is of 2 out of 3 hardware architecture with implementations of the fail safety principles. It complies with the CENELEC standards and conforming to Safety Integrity Level - 4 (SIL-4).
- The system incorporates auto features and eliminates manual co-operations from other end for Line Clear and Line Close operations.
- Emergency cancellation at the receiving station.
- Automatic Train On Line.
- Automatic Line Close after sequence proved at receiving end and section is free.
- Simplified Block Back / Block Forward Operations.
- Cooperative Cancellation.
- Line Clear Block Key (LCB Key) to prevent automatic granting of Line Clear.
- Station Master Key (SM Key) to prevent unauthorized panel operations.
- Station Master Key (SM Key) to prevent unauthorized panel operations.
- Single Line Working with provisions for shunting with shunt key EKT
- Event logging operations and data storage in built in the system.
- Data logger network interface.
- Communication media: (1 pair cable in quad or on voice channel in OFC.)
- Block bell and telephone on separate pair of quad or voice channel of OFC.
- Two repeater relays to repeat input status at the other end.
Safety Features :
- Safe shutdown if the output is less restrictive.
- Mine field in the non-program area for trapping the CPU.
- Inputs and Outputs are exchanged and validated among 3 CPUs in Inter Processor
- communication before delivering to independent voter module.
- Continuous monitoring of system cycle time. In case of deviation safe shutdown of system.
- 2 Bit bi-state control for all the vital output relays.
- Continuous monitoring of output for every 50ms.
- Online Hardware diagnosis and self checking.
- Fault detection and negation failsafe measures.
Advantages:
- Less maintenance and requires no periodical over-hauling in consideration with the electromechanical systems.
- It considers signal overlap distance for granting line clear, which is not available in some of the present systems.
- It has inbuilt data logging capability which logs all the panel operations, events, relays status and other information.
- All the panel indications are with LEDs.
- No need for next train on PLC after push back operation.