The double side tripping device is used to realize the DC switch tripping function between two metro traction stations. At present, the DC switch cabinet for metro traction power supply adopts multi-core control cable to transmit electric pulse signal to realize the joint tripping function of DC switch between two traction stations. Although the scheme is mature and the reliability meets the requirements, it will cause problems such as complex design, difficult construction and maintenance, limited transmission distance and lack of signal channel monitoring.FMT100 uses optical cable instead of cable to transmit signal, and realizes the function of replacing multi hop cable by means of communication and logic programming, which can make the whole design, construction and maintenance process simple and easy.