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Entry type: FAQ Entry ID: 21628604, Entry date: 06/20/2005
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CP 342-5 -- Why does my CP 342-5, operating as a DP master or DP slave, not switch to data transfer, even though the CPU is in RUN mode?

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Description:
The CP 342-5 only goes into data transfer mode if you call call the "DP_SEND" (FC 1) or "DP_RECV" (FC 2) blocks in the user program.

DP master mode:
This operating state is OFFLINE as long as the blocks are not called (the BUSF LED flashes in the 6GK7 342-5DA02-0XE0 and 6GK7 342-5DF00-0XE0).

DP slave mode:
The response of the module varies depending on the release:
 

CP order number Operating mode
6GK7 342-5DA00-0XE0 OFFLINE as long as the blocks are not called.
6GK7 342-5DA01-0XE0 OFFLINE as long as the blocks are not called.
6GK7 342-5DA02-0XE0 The DP slave has a configuration of 0 bytes of input data and 0 bytes of output data. Since this data does not match the configuration which is defined in the DP master, no data transfer can take place (BUSF LED flashes).
6GK7 342-5DF00-0XE0 The DP slave has a configuration of 0 bytes of input data and 0 bytes of output data. Since this data does not match the configuration which is defined in the DP master, no data transfer can take place (BUSF LED flashes).

Note:
Whenever you operate the module as a DP slave, always ensure that the data in the block call (in the DP slave station) is exactly the same length as the I/O data which is configured in the DP master for this DP slave.
Also refer to the entries entitled the "Requisite version of the function blocks for operating the CP 342-5" - Entry ID: 187699 and "Frequent user errors when using the CP 342-5 as a DP master" - Entry ID: 18208090.

History:
FAQ 2969511 has been incorporated into the present FAQ and deleted as a separate FAQ.

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