Medha’s Electronic Interlocking System MEI 633 is a fail-safe, state-of-the-art Distributed Interlocking System. The System has been designed to CENELEC Standards to meet SIL-4 safety specification. It is based on two out of two architecture with a hot standby provision and automatic change-over facility. The System provides all the Interlocking features including Route Setting, Route Release, Point Operation, Track Occupancy Monitoring, Overlap Protection, Crank Handle Operation, Level Crossing Gate Interlocking, and provision for Block working.
Central Interlocking Unit (CIU) uses two-out-of-two architecture with two independent channels computing the vital interlocking logic and a supervisory processor monitoring the two vital computing channels. Hot standby with automatic change-over facility is provided. Redundant communication channels to Object Controller (OC) and Panel Processor (PP) are provided through two communication processors. OFC interface with ring configuration is used for communication between CIU and OC and CIU and PP.
Object Controllers (OCs) control the field gear through fail-safe signaling relays. CIU supports up to 32 OC units. Each OC can handle 24 vital outputs and 40 vital inputs. Each OC has two communication modules for redundancy. Each OC has 8 Wayside Function Modules (WFMs), each capable of handling 8 vital inputs or 8 vital outputs. WFM uses two-out-of-two architecture with two independent channels handling Vital input / outputs.
Panel Processor (PP) provides the interface between Operator's panel and CIU. Windows based graphical user friendly Application Data Generation tool suite with high level of automation is provided for generation of yard specific Application data. The tool suite also provides the facility for reverse compilation and relay diagram generation for easy verification of Application data.
Maintenance Terminal provides a diagnostic interface through online and off-line event, fault and yard status display with date and time stamps. It records all the events and faults for later off-line analysis.