The rod control and rod position systems in No.1 reactor of Qinshan nuclear power plant have been remodeled into digitized systems.The digital systems were achieved by PLC logic control functions

and a human-machine interface was used for online monitoring of system status and parameter changes.Redundant configuration was adopted for PLC controller to improve the system flexibility and reliability.The original analog circuits were modified into double-hold circuits against failures.Redundant communication between the rod control and rod position system was used to reduce the numbers of field cable.A data collection cabinet was designed to sample the coil waveform data on the drive mechanism for real-time data acquisition and facilitate post-accident analysis.