The programmable logic control unit (LCU) addresses the problems of frequent failures, detection difficulties and maintenance difficulties of train relay control circuits caused by aging, electromagnetic, vibration, temperature changes and various types of load changes under the effect of complex environments. Through distributed programmable and safety control technology based on ""multi-group redundancy"" and contactless control and drive technology based on signal acquisition and self-diagnosis technology, it realizes complete replacement of traditional relays in vehicle electrical control systems, directly controls and drives train control signals and electrical equipment, fundamentally solves the shortcomings of traditional touch logic control circuits, improves the safety and reliability of vehicle control, improves the economy and convenience of operation, and meets the demand for improved safety service performance of train control circuits under the effect of complex environments. Break the traditional vehicle electrical state can not sense the situation, the control, state information digital, for intelligent vehicles to provide intelligent control and data support. Features: Highly integrated, digital electrical, maintenance-free design concept, intelligent, easy graphic design for secondary development.