Siemens SIMATIC S7-300 Hardware And Installation Manual page 132

Commissioning
Initial power up for a CPU with memory card (MC)
The CPU 312 IFM has no memory card, but it is covered in this section.
Switch on the PS 307 power supply module.
Result:
• The 24 VDC LED on the power supply module is lit.
• The 5 VDC LED on the CPU
is lit.
–
The STOP LED flashes at 2 Hz when the CPU executes an automatic
–
memory reset.
The STOP LED is lit after memory reset.
–
The BATF LED is lit if the back-up battery is missing in the CPU (not with
CPU 312 IFM, since not buffered).
Note
If you insert a Memory Card and a back-up battery before power is on, the CPU
also requests a memory reset after start-up.
Initial power up for a CPU with micro memory card (MMC)
Switch on the PS 307 power supply module.
Result:
• The 24 VDC LED on the power supply module is lit.
• The 5 VDC LED on the CPU
is lit.
–
The STOP LED flashes at 2 Hz when the CPU executes an automatic
–
memory reset.
The STOP LED is lit after memory reset.
–
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S7-300 Programmable Controller Hardware and Installation
A5E00105492-02