What are examples of ratio variables?
Examples of ratio variables include: enzyme activity, dose amount, reaction rate, flow rate, concentration, pulse, weight, length, temperature in Kelvin (0.0 Kelvin really does mean “no heat”), survival time.
What are the 5 most common process variables?
The most common process variables fall into five major types: level, flow, pressure, temperature, and analytical.
Which is the slowest process variable?
The key factor in sensor response is the measured variable — pressure and flow measurements are usually fast, temperature slow, and composition slowest.
What is a control in a process?
Process Control is the active changing of the process based on the results of process monitoring. Once the process monitoring tools have detected an out-of-control situation, the person responsible for the process makes a change to bring the process back into control.
What is a process variable in control system?
A process variable, process value or process parameter is the current measured value of a particular part of a process which is being monitored or controlled. The current temperature is called the process variable, while the desired temperature is known as the set-point.
What is the main object of process control?
The objective of process control is to keep key process-operating parameters within narrow bounds of the reference value or setpoint. This chapter describes the theory behind control circuits to maintain automatic control over a process. The basis of automatic control is the control loop.
What are the main components of process control?
All process control configurations, whether manual, automatic, or computer-based, have three essential elements:
- a measurement (often several);
- a control strategy (embedded in a controller);
- a final element for implementing the control action (a valve, heater or other variable input).