PID closed loop control or proportional-integral-derivative control is a useful software tool that can be used within an ABB Variable Speed Drive. But what exactly is it? The PID controller is the most commonly used method of closed looped control to a variable speed drive. This is predominantly used in industrial control systems to produce accurate and consistent operation, whether this may be a fan blowing at a variable speed to cool a product to a constant set point temperature or perhaps a pump pumping a liquid at a variable speed to a set point level or flow. The way this works is by an actual process feedback signal into the VSD PID controller that allows very minimal error. A sensor would be employed into the process whether this is a pressure sensor, flow sensor, temperature sensor, or CO2 sensor it would usually be fed back on a 4-20ma signal. This accurate control saves energy and provides a consistent process which can reduce waste.
Darren Beeby explains…