Siemens CP 343-1 - Manual (Page 21)

6 Configuring and Programming the CP as a PROFINET IO Device
B3L−21
CP 343-1 Lean for Industrial Ethernet / Manual Part B3L
Release 03/2007
C79000-G8976-C198-04
6.2 Principle of Data Exchange over PROFINET IO
Data Exchange between controller and CP as PROFINET IO device
Data exchange between a PROFINET IO controller and PROFINET IO device
involves the following procedure:
S On the PROFINET IO controller
Data exchange is initiated by the PROFINET IO controller that writes output
data to the configured output area (O addresses) and fetches input data from
the configured input area (I addresses).
S On the PROFINET IO device
Data is processed by the CP in the PROFINET IO device on the interface to the
PROFINET IO controller.
Communication within the PROFINET IO device involves calling the FCs
PNIO_RECV and PNIO_SEND in the user program of the CPU.
PROFINET IO
CP CPU
STEP 7
user program
CP
database
PROFINET
IO controller
PROFINET IO device
Receive
Send
PROFINET IO
data areas (DB,
bit memory)
PNIO_RECV
PNIO_SEND
Process
outputs
Process
inputs
Configured
O addresses
Configured
I addresses
Figure 6-1 Interaction between PROFINET IO Device and PROFINET IO controller
Note
In the CPU of the device, the IO data areas for input data and output data are
transferred as an entire area to or from one of the data areas (DB, bit memory)
including any gaps.