Design of slave station control system for slurry circulation in slurry shield machine

Taking the Herrenknecht shield machine as an example, a slave station control system for slurry circulation, independent from the master station control system, is designed to seamlessly connect to the shield machine control system.The slave station is composed of slurry pump control cabinet, valve control box and ground monitoring station. The S7-200PLC is selected for the control and the Profibus-DP is used for communication with the master station. In groundmonitoring station, a combination of S7-200PLC+Profibus-DP modulus+computer terminal is designed to synchronously display the operation conditions of pumps and valves. The slurry pump is driven by AC motor, with its speed controlled by aschnielder Altivar 71 frequency convertor, a Profibus-DP communication card and a S7-200PLC. The Profibus-DP networkand Siemens S7 series PLC are utilized to construct the overall system with twin-core CAT 5 cable as the transmission mediain the bus, with the transmission speed up to 12 MBP. Optoelectronic isolation relay amplifiers are added in every local controlcabinet, which can solve the problems in long-distance shield tunneling communication signal transmission attenuation andelectrical safety in the tunnel.