The invention discloses a 
Profibus-DP photoelectric 
signal conversion 
system. The 
Profibus-DP photoelectric 
signal conversion 
system comprises a photoelectric converter, a data receiving and transmitting 
logic control circuit and an electric isolation and differential 
signal conversion circuit, wherein the photoelectric converter receives optical signals and converts the optical signals into TTL level signals, or receives the TTL level signals and converts the TTL level signals into the optical signals; the data receiving and transmitting 
logic control circuit comprises a three-state buffer connected with the photoelectric converter, and a receiving and transmitting control end of the three-state buffer is sequentially connected with a 
delay circuit and a first Schmitt 
inverter; the electric isolation and differential signal conversion circuit comprises a differential 
level converter, the differential 
level converter is connected with the photoelectric converter and is used for receiving and transmitting the TTL level signals, the differential 
level converter is connected with an output end of the first Schmitt 
inverter and is used for receiving, transmitting and controlling 
temporal logic signals, and an output end of the differential level converter is connected with a 
Profibus-DP 
bus and is used for receiving and transmitting Profibus-DP differential signals. The Profibus-DP photoelectric signal conversion 
system provided by the invention has greater real-time performance and flexibility.