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Entry type: FAQ Entry ID: 109474577, Entry date: 03/13/2015

How do you run diagnostics on the PROFIBUS of a CP50M1?

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Unwanted reactions might occur when running the diagnostics of PROFIBUS slaves in the SIMATIC Manager. Therefore you should use the FBs DPDIAG and SPSLDG to run the diagnostics.

If, for the slave diagnostics in the SIMATIC Manager, you right click the CP50M1 (6DD1661-0AD1) and select "PLC/Hardware Diagnostics", there is a display of the PROFIBUS stations which report diagnostics.
If you then select a slave station to display the module information, you get a message indicating that the inserted module and the configured module are not identical.

Fig. 01

When you confirm this message there is a crash of the CPU 551 with "H" and the CP50M1 flashes with all LEDs (H1, H3, H5 green, H7 orange, H4, H6 red).
The only way to get the system running again is to do an overall reset.

You can avoid this behavior by running the diagnostics in the SIMATIC TDC program instead of the slave diagnostics in the SIMATIC Manager.

  1. Use the function block DPDIAG (diagnostics overview PROFIBUS DP) to determine which stations have registered diagnostics.
  2. Use the function block DPSLDG (slave diagnostics PROFIBUS DP) to display the diagnostics data of a slave.

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