The control variables are what we keep the same during the experiment to make sure it’s a fair test. Variables. In this experiment the: Independent variable is the volume of the object.

Remember - these variables are controlled (or kept the same) because to make it a fair test, only 1 variable can be changed, which in this case is the current.

Typically, process control loop feedback strategies use “flow” as the manipulated variable to control the desired variable. To achieve this, a controller output signal is sent to a control flow valve ...