Consistent Data - Siemens SIMATIC S7-300 Hardware And Installation Manual

8.7

Consistent data

Consistent data
The table below illustrates the points to consider with respect to communication in
a DP master system if you want to transfer I/O areas with "Total length"
consistency.
CPU 315-2 DP
(6ES7 315-2AF03-0AB0)
(6ES7 315-2AF83-0AB0)
CPU 316-2 DP
CPU 318-2 DP
(firmware version < V3.0)
Even if they exist in the
process image, consistent
data is not automatically
updated.
To read and write consistent
data, you must use SFC14
and 15.
You can transfer a maximum of 32 bytes of consistent data.
S7-300 Programmable Controller Hardware and Installation
A5E00105492-02
CPU 318-2 DP
(firmware version • 9
You can choose whether or
not to update the address
area of consistent data in the
process image.
To read and write consistent data, you can also use SFC14
and 15.
If the address area of consistent data is not in the process
image, you must use SFC14 and 15 to read and write
consistent data.
Direct access to consistent areas is also possible (e.g.
L PEW or T PAW).
Addressing
CPU 315-2 DP
(6ES7315-2AG10-0AB0)
CPUs 31xC
The address area of
consistent data in the
process image is
automatically updated.
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