Platform Screen Door Interface Solutions in Signaling System Upgrading and Renovation

［Objective］When urban rail transit signaling systems reach their lifespan end, the aging signaling equipment must be upgrade and renovated. The PSD (platform screen door) interface is a crucial part in signaling system upgrade. Since the renovation cycles of PSD and signaling system are not synchronized, it is essential to develop a PSD interface solution during the signaling system upgrade to ensure compatibility between the new signaling system and the existing PSD, while maintaining the interface functionality between them during the transition process of signaling system upgrade. ［Method］The adaptation of the new signaling system to existing PSD interface and the PSD reverse connection scheme between new and old signaling systems are key challenges in the signaling system renovation process. Based on the PSD interface solution of a specific signaling system upgrade project in China, the interface functions between the signaling system and PSD are explained, the interface time sequence of signaling system control commands using pulse and continuous signal methods separately is analyzed. Considering the characteristics of existing PSD interface circuit and new signaling system, a modification method for existing PSD interface circuit renovation is proposed, allowing the new signaling system to be compatible with the existing PSD interface. A reverse connection scheme for PSD interface is also designed to ensure a smooth transition between the new and old signaling systems. ［Result & Conclusion］The proposed PSD interface solution in the signaling system upgrade and renovation ensures seamless transitions between the old/new signaling systems and PSD interfaces, while also improving the reliability of the PSD interface to some extent.