fischertechnik COMPUTING ROBO TX ElectroPneumatic, Manual

ROBO TX ElectroPneumatic

COMPUTING

5

The air moves this cylinder in one direction only. It is returned to its initial position by the force of a 
spring. Such cylinders are called "single acting cylinders". 

Note:

The connection you use to move out (extend) the piston is designated "A"; the piston is pulled back (re-
tracted) with the aid of a spring.

Air can be compressed

Anyone working with pneumatic equipment today should know something about the physical properties 
of air. You can use a little test for this purpose: 

Pull the red piston rod in the cylinder all the way out. Then hold connection A shut with your finger. 
Now release the piston rod. What can you observe?

The piston rod is pulled back only a short distance by the spring. 

Result:

The air in the cylinder is pressed together (compressed) preventing the piston rod from moving. The 
more air compressed, the greater the air pressure in the cylinder. This pressure can be measured with a 
pressure gage or also calculated. The unit of measure for pressure is 

”bars”

 or 

”Pascals”

You can remember the following equation for this:

Pressure = force/area or p = F/A

From this equation you can see that the pressure depends on the force exerted on a round surface in the 
cylinder.

Generating and storing compressed air – diaphragm pump as compressor 

The diaphragm pump included in the construction set supplies the compressed air required for you to 
control the individual models. In industrial circles this is known as the compressed air source.

Mode of operation:

A diaphragm pump consists of two chambers 
separated by a diaphragm (membrane). In one 
chamber the resilient diaphragm is moved up 
and down by a piston or cam. During the down-
ward stroke the diaphragm is pulled back and 
air is pulled into the second chamber through 
the inlet valve. When the piston moves up, the 
diaphragm presses the air out of the pump head 
through the outlet valve.

Note:

The pressure generated by the compressor is approx. 0.7 to 0.8 

bars

. The diaphragm pump is mainte-

nance-free.

Circuit diagram of single 

acting cylinder

Pressure gage for  

measuring air pressure

Compressor

Circuit diagram of 

compressed air source

Piston

Cylinder

Diaphragm

Inlet/outlet valve

Cover

Crank drive