Siemens SIMATIC Manual page 10

2. Wiring
Warning
!
You may come into contact with live wires that are connected to the power supply.
Make sure that the S7-300 is completely disconnected before you start wiring.
Wiring the Power Supply and the CPU
Step
1 Open the front panels of the power supply and the CPU.
2 Detach the strain relief clip from the power supply.
3 Strip the flexible power cable, crimp on the ferrules and connect
them to the power supply.
(Blue to terminal M, black to terminal L1, protective conductor to terminal PE)
4 Screw the strain relief clamp in place.
5 Now wire the power supply to the CPU using the
2
1 mm cross-section flexible cable.
Strip the ends to approx. 6 mm and crimp on the ferrules.
Connect terminals L+ and M on the power supply to those on the CPU.
6 Check that the line voltage selector switch is set to the correct line voltage.
The power supply is set at the factory to a line voltage of AC 230 V. To change the voltage,
remove the protective cap with a screwdriver, set the switch to the required line voltage and
replace the protective cap.
Wiring the Digital Input and Output Modules
Step
1 Open the front panels of the digital input and output modules.
2 Push front connectors into the DI and the DO until they snap into position. The front
connectors still stick out of the module, and thus have no contact with the module, in this wiring
position.
3 Cut around 10 wires (1mm
4 Wire the front connector for the digital input module as follows:
Terminal L+ to terminal L+ on the power supply; terminal M to terminal M on the power supply
Terminal 3 to the first connection of switch 1;
Terminal 4 to the first connection of switch 2
Connect the two unassigned connections on switches 1 and 2 to L+ on the power supply.
5 Wire the front connector for the digital output module as follows:
Terminal L+ to terminal L+ on the power supply; terminal M to terminal M on the power supply
6 Lead the wires downwards out of the front connectors.
8
Wiring the power supply and CPU
Wiring the Front Connectors of the DI and DO
2
) to length (20 cm), and attach ferrules to the ends.
S7-300 Automation System CPU 31x: Commissioning
A5E00164278-02