A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. The output signal of an ideal sensor is linearly proportional to the value of the measured property. There are numerous types of sensors. Some common sensors measure electric properties (amps, volts), product flow, distance, pressure, force, temperature, proximity, presence.
The Proportional-Integral-Derivative Controller uses feedback from a process to adjust the control of the process.
The PID Controller attempts to correct error between a measured process value and a setpoint value. This is done by calculating and outputting a corrective action that can be applied to the process control.
Integrating PLC, HMI & SCADA Systems for YOUR APPLICATION
Process Control and Industrial Automation terms and basics
Numerous tools are available to the ‘Integrator’ to provide automation and control to processes, machines or entire plants. Following are some of the terms and basics of the trade.
The Programmable Logic Controller is a specialized computer designed specifically for control of processes. PLC’s are often the main element in a automation or control process. They are very industrial robust and can operate in the typical industrial environment - extended temperature ranges, immunity to electrical noise and resistance to vibration.
operator, allowing the operator to monitor and control the process.
The Human Machine Interface is the link between the Operator and the Control Devices. The HMI presents real time data to a human
Supervisory control and data acquisition equipment gathers and analyse’ real time data. SCADA equipment collects data from sensors and machines on the shop floor or in remote locations and sends them to a central computer for management and control. SCADA warns when conditions become hazardous by sounding alarms.
A motor controller is a device or group of devices that serves to govern in some predetermined manner the performance of an electric motor. A motor controller might include a manual or automatic means for starting and stopping the motor, selecting forward or reverse rotation, selecting and regulating the speed, regulating or limiting the torque, and protecting against overloads and faults.
HMI’s range from simple inexpensive touch panels to very elaborate PC based systems.