Operations In The Cpu During A Memory Reset - Siemens CPU 313C Hardware And Installation Manual

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Table 9-5

Operations in the CPU during a memory reset

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CPU activities 1.
2.
3.
4.
Memory contents The user program is transferred from the MMC to the main memory again and the
after reset memory utilization is displayed accordingly.
What's left? Data in the diagnostics buffer.
You can read the diagnostic buffer with the PG (see 67(3  2QOLQH +HOS).
•
The MPI parameters (MPI address and highest MPI address, transmission rate,
configured MPI addresses of CPs/FMs in an S7-300).
•
The same also applies to the CPU 317-2 DP, if the MPI/DP interface of the CPU
was assigned as a DP interface (PROFIBUS address, highest PROFIBUS
address, baud rate, setting as active or passive interface).
Content of elapsed time counter
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MPI parameters (or DP parameters in the case of MPI/DP interfaces) have a
special setting for memory reset. The table below describes which interface
parameters are valid after the memory reset.
With MMC inserted
Without micro memory card (MMC) inserted
S7-300 Automation System, Hardware and Installation: CPU 31xC and CPU 31x
A5E00105492-03
The CPU deletes the entire user program in the main memory.
The CPU deletes the retentive data.
The CPU tests its own hardware.
The CPU copies the sequence-relevant content of the MMC (load memory) to
the main memory.
7LS If the CPU cannot copy the MMC and prompts you for a memory reset:
•
Remove the MMC
•
Reset CPU memory
Read the diagnostic buffer.
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MPI parameter on the MMC or integrated
read-only load memory are valid. If this
location does not contain parameter data
(SDB), the previously set parameters stay
valid.
... are retained and valid.
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