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Entry type: FAQ Entry ID: 10535268, Entry date: 03/27/2002

Abort with protocol error 8004 when copying from RAM to ROM 

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Why do the CPUs 312-IFM and 314-IFM abort copying from RAM to ROM with the error message "Protocol error 8004"?

The error message "Protocol error 8004" indicates that there is data in your CPU which is not mutually consistent.
Inconsistent data can occur if you have processed the configuration data in the CPU with non-Siemens software or with different versions of STEP 7. You have to do an overall reset of the CPU. Proceed as follows to do this.

  • Save your program (e.g. by loading it into the PG).
  • Switch off the power supply of the CPU (Power OFF).
  • Hold the key switch in the MRES position and switch the power supply of the CPU on again. Keep holding the switch in the MRES position until the STOP LED of the CPU lights continuously.
  • Now your CPU has been reset completely and you can load and save your CPU as usual.

Consistency, Save, Data backup 

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