This trainer provides a comprehensiveexperimental introduction to the fundamentals of control engineering using anexample of continuous pH control.
A caustic solution is added to fresh water byway of a metering pump. The pH value of this solution is measured. The acid isthen added to the solution as a neutralizing reagent by way of a secondmetering pump. The chemical reaction occurs in a pipeline system. The pH valueis then remeasured. A state-of-the-art digital industrial controller controlsthe second metering pump with reference to this pH value. The neutralisedsolution flows into the product tank. A third manual measurement of the pHvalue in the product tank permits disposal of solution with a neutral pH value.The pH value of the input solution can be varied by manually adjusting themetering pump or by varying the quantity of fresh water. This enablesdisturbances to be simulated. The controlled variable X and the manipulatingvariable Y are plotted directly on an integrated 2-channel line recorder.Alternatively, the variables can be tapped as analogue signals at lab jacks onthe switch cabinet. This enables external recording equipment, such as anoscilloscope or a flatbed plotter, to be connected.