A waste-water processing system with host computer and on-the-spot unit control

As the IBM-PC and its compatible computers are universally applied, the application of industrial personal computers (IPCs) with the ISA PC-bus has become increasingly popular. This paper gives an example with two-level control: an IPC is employed in the waste-water processing system as a host computer and an 8751 MCS-51 single-chip processor as an on-the-spot unit. The authors analyse the control state of the system and employ the differential PID control as a practical solution to the process control of the waste-water processing plant. They also propose other means of processing and resisting the interference on the control signals.