3Installing and wiring the hardware
Note
To make the example easier to follow, we will use colored momentary contact switches. You can implement the exam- ple with commercially avail- able momentary contact switches of any color. 
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Testing the connections
Now, test your wiring to verify that it is functioning properly.
For this purpose, take turns pressing the momentary contact switches and observe the LEDs on the inputs of the CPU. Whenever an input is activated, the corresponding LEDs always light up.
•Press the green momentary contact switch for “Motor ON”. The LED of input
0.0(terminal 2) will light up.
•Press the red momentary contact switch for “Motor OFF”. The LED of input
0.1(terminal 3) will light up.
•Press the right momentary contact switch for “Clockwise rotation”. The LED of input 0.2 (terminal 4) will light up.
•Press the left momentary contact switch for “Counterclockwise rotation”. The LED of input 0.3 (terminal 5) will light up.
You have installed, wired, and tested all components. Next, you will create the control structure in STEP 7 Lite and download the configuration to the
CPU 312C.
SIMATIC