Introduction to Industrial Automation

5.9   Electro-Pneumatic  Applications

In Section 5.9, we present a set of more complex electro-pneumatic automations where initially 

the problem will be described, followed by the desired operation, the diagram “position-steps” if 

needed, the pneumatic circuit, and the electric automation circuit.

5.9.1   Industrial Automation of an Arrangement 

for Separating Similar Balls

In Figure 5.23, a simple mechanism for separating similar balls coming from a feeder is presented. 

A double-acting cylinder is moving the carrier of the balls left and right, at such a speed that in 

each translation, extension, or retraction, the mechanism receives a ball and then, due to gravity, 

releases it in the corresponding inlets 1 and 2. It should also be noted that the regulation of the 

speed for this translation mechanism is performed by a special valve in the pneumatic circuit.

The overall installation is set in operation or terminated by a manual START-STOP command. 

The proximity switches detect the pass of a ball in the corresponding inlets. The required pneumatic 

and electric circuits are presented in Figure 5.23a and b, respectively. In the rest state of operation, 

the valve is de-energized and the cylinder is fully extended. By pressing the START button, after 

checking that balls exist in the feeder, the automation starts normally and the overall setup will be 

able to separate the balls. If there are no balls in the supply chain, the piston rod will be translated to 

the right, the cylinder will be retracted and it will remain in this state, even if balls are supplied later. 

In this case, for repeating the separation procedure, the stop button should be pressed first, and then 

the START button again. It is obvious that a better design of the overall automation can be achieved 

in order to perform the same operations in a more autonomous approach.

Cylinder A

Cylinder B

Up

Down

Out

In

t

t