Siemens CP 343-1 - Manual (Page 28)

6 Configuring and Programming the CP as a PROFINET IO Device
B3L−28
CP 343-1 Lean for Industrial Ethernet / Manual Part B3L
Release 03/2007
C79000-G8976-C198-04
Data consistency
The length information in the block call must be identical to the total length of the
input or output data configured for this PROFINET IO device.
The entire input or output data area of the PROFINET IO controller is transferred
in its entirety between the CP and CPU and is therefore consistent.
Note: Remember, however, that in terms of the “IO user data” within a PROFINET
IO system, only the data consistency of individual IO slots can be guaranteed. This
applies regardless of whether consistent data transfer between the CPU and CP is
guaranteed for the blocks described here.
6.4.2 Initialization and Configuration
Initialization
As a PROFINET IO device, the CP requires the following information in the user
program for configuration by the PROFINET IO controller at every startup:
S Length of the input data (when FC11 is called)
S Length of the output data (when FC12 is called)
When the connection is established between the PROFINET IO controller and the
PROFINET IO devices of a PROFINET IO line, the entire length of the input and
output data is checked. The PROFINET IO controller compares the configured
entire length of the input and output data with the LEN parameter of FC11 and
FC12 in the user program of the device for every PROFINET IO device.
If the length information for the input and output data does not match, the block is
terminated with an error.
During this initialization phase, the two blocks must be called until FC11 signals
DONE=1 and FC12 signals NDR=1.
Notice
Remember that the successful configuration by the PROFINET IO controller is
only possible after local initialization by the FC calls PN IO_SEND (FC11) for the
input data and PN IO_RECV (FC12) for the output data.
Note
During initialization, the data of PNIO_SEND (FC11) is not evaluated and the data
of PNIO_RECV (FC12) is initialized with default values.
FC11 and FC12 transfer valid data only following the subsequent calls.