Digital control of process parameters - employs number of microprocessors controlled from CPU with digital regulator connected through interfaces

摘要

Industrial processes require the control of a wide range of parameters such as flow, levels and temp. These are controlled from sensers via a digital control system in which a number of microprocessors are controlled from a central unit. This provides a high degree of safety under fault conditions. A calculator is connected via an interface to a data bus to which a VDU and keyboard are also connected. A bus controller allows a control VDU to be connected. A digital regulator comprises a microprocessor with a programmable memory acting as a central control unit. An interface permits connection to the bus. Sensors provide input signals for the central control unit which are processed by interface circuits containing A/D and D/A converters. This allows the control unit to determine the setting of regulator valves.