Wiring The Power Supply Module And The Cpu - Siemens Simatic S7-300 CPU 31xC Series Installation And Operating Instructions Manual

6.4

Wiring the power supply module and the CPU

Requirements
All modules are mounted onto the rail.
Wiring the PS and CPU
Note
The PS 307 power supply module is equipped with two additional 24 VDC terminals L+ and
M for the supply to I/O modules.
Note
The power supply connector of your CPU is a plug-in device and can be removed.
Warning
There is a risk of contact to live wires if the power supply module, or any additional load
power supply units, are connected to the mains.
You should therefore isolate the S7-300 from power before you start wiring. Always use
crimp ferrules with insulating collars for the conductors. Close all front panels of the modules
when you completed the wiring. This is conditional before you reconnect the S7-300 to
power.
1. Open the PS 307 power supply module and CPU front panels.
2. Open the strain relief on the PS 307.
3. Strip the power cable to a length of 11 mm and connect it to L1, N and to the protective
4. Screw-tighten the strain relief again.
5. Next, wire the PS and CPU
S7-300, CPU 31xC and CPU 31x: Installation
Operating Instructions, Edition 08/2004, A5E00105492-05
earth (PE) terminal of the PS 307.
The power supply connector of the CPUs is a removable plug-in device.
Strip the connecting cables for the CPU power supply to a length of 11 mm. Wire the
lower terminals M and L+ on the PS 307 to terminals M and L+ of the CPU.
6.4 Wiring the power supply module and the CPU
Wiring
6-5