Introduction to Industrial Automation

Figure 3.26  Automatic operation of two pumps according to the demand.

Photocell 

Limit switch

Inversion

motor 

b

1

b

2

Photocell-sensor (u) 

Limit switch

Figure 3.27  An electrically driven gate with sensors for automatic operation.

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  Introduction to Industrial Automation

automation is achieved by the utilization of a remote control of two channels (two independent 

signals), one for every direction of movement. The automation circuit is presented in Figure 3.28. 

As long as a button from the remote control transmitter is being pressed, a corresponding contact 

at the receiver (TC

1

 or TC

2

) remains closed, thus retaining the movement (more automatic opera-

tion) of the latch principle that needs to be utilized. A similar operation of the door can also be 

achieved through a remote control transmitter of one channel. In this case, the automation circuit 

is different and the utilization of a pulse relay is needed.