Siemens SIMATIC MV420, Operating Instructions Manual

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Process interfacing via an automation system (PLC, PC)
10.1 Integration via Onboard PROFINET IO
SIMATIC MV420 / SIMATIC MV440
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Operating Instructions, 04/2013, A5E02371045-06
10.1.2 Configuration for using the FB 79
"FB79" must be selected in HW Config catalog to use the FB 79 or the associated
PROFINET IO interface without a function block.
Figure 10-3 HW Config with SIMATIC MV440 reader (screenshot for SIMATIC MV420 similar)
In the configuration example, the control byte of the reader was placed at output address 0
and the status byte at input address 0 of the CPU (slot 1). If these addresses are located in
the process image of OB1 (process image partition "OB1-PI"), then you can work here using
process image access (for example "A I0.6" or "S Q0.1"). If this is not the case, you will have
to work with direct I/O access (for example, "L PIB 0").
The start of the 16-word long consistent communications area of the reader is placed at input
address 256 and output address 256 (slot 2). If these addresses are located in the process
image of OB1 (process image partition "OB1-PI"), you can work with process image access
in OB1 (for example "L IW 2", "T QB 1") without losing consistency. (This only applies to
CPUs that transfer consistent user data via the process image.)
If these addresses, on the other hand, are not located in the process image of OB1, you will
have to access the communications area of the reader using SFCs 14 "DPRD_DAT" and 15
"DPWR_DAT" to ensure consistency.