Siemens SIMATIC ET 200AL, System Manual

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S7 communication
Communication
Function Manual, 05/2021, A5E03735815-AJ
139
Instructions for S7 communication
For S7 communication with S7-1500, the following instructions can be used:
•
PUT/GET
You write data to a remote CPU with the PUT instruction. You can use the GET instruction
to read data from a remote CPU. The PUT and GET instructions and are one-sided
instructions, i.e. you need only an instruction in one communication partner. You can can
easily set up the PUT and GET instructions via the connection configuration.
Note
Data blocks for PUT/GET instructions
When using the PUT/GET instructions, you can only use data blocks with absolute
addressing. Symbolic addressing of data blocks is not possible.
You must also enable this service for protection in the CPU configuration in the
"Protection" area.
This FAQ ( https://support.industry.siemens.com/cs/ww/en/view/82212115 ) provides
information about how to configure and program an S7 instruction and the GET and PUT
communication instructions for data exchange between two S7-1500 CPUs.
• BSEND/BRCV
The BSEND instruction sends data to a remote partner instruction of the type BRCV. The
BRCV instruction receives data from a remote partner instruction of the type BSEND. You
use the S7 communication via the BSEND/BRCV instruction pair for secure transmission of
data.
• USEND/URCV
The USEND instruction sends data to a remote partner instruction of the type URCV. The
URCV instruction receives data from a remote partner instruction of the type USEND. You
use the S7 communication via the USEND/URCV instruction pair for fast, non-secure
transmission of data regardless of the timing of the processing by the communications
partner; for example for operating and maintenance messages.