Siemens Industry Online Support
Siemens AG
Entry type: Product note Entry ID: 13885262, Entry date: 12/05/2002

Communication problems between the CPU and FM-NC with operator control device

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When using the more recent S7-CPUs, problems can be encountered for the communications to the operator control device of the FM-NC.

With the new CPUs (e.g. CPU315-2DP, 6ES7 315-2AFx3-0AB0), problems can occur, e.g. when displaying the status of the PLC using the operator device.

This problem can be caused by a setting in the CPU which can be easily changed.

More detailed information on the CPUs involved and to resolve the problem can be taken from the FAQ ID: 12604880 "No cyclic read task possible for CPU 314/315 – error message 33:55301(D805)".

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