Easy to communicate between devices
7.8 S7 communication
Easy Book
Manual, 03/2014, A5E02486774-AF
153
You can use the GET and PUT instructions to communicate with S7 CPUs through
PROFINET and PROFIBUS connections. This is only possible if the "Permit access with
PUT/GET communication" function is activated for the partner CPU in the "Protection"
property of the local CPU properties:
● Accessing data in a remote CPU: An S7-1200 CPU can only use absolute addresses in
the ADDR_x input field to address variables of remote CPUs (S7-200/300/400/1200).
● Accessing data in a standard DB: An S7-1200 CPU can only use absolute addresses in
the ADDR_x input field to address DB variables in a standard DB of a remote S7 CPU.
● Accessing data in an optimized DB: An S7-1200 CPU cannot access DB variables in an
optimized DB of a remote S7-1200 CPU.
● Accessing data in a local CPU: An S7-1200 CPU can use either absolute or symbolic
addresses as inputs to the RD_x or SD_x input fields of the GET or PUT instruction,
respectively.
STEP 7 automatically creates the DB when you insert the instruction.
Note
To ensure data consistency, always evaluate when the operation has been completed
(NDR
= 1 for GET, or DONE = 1 for PUT) before accessing the data or initiating another
Note
V4.0 CPU program GET/PUT operation is not automatically enabled
A V3.0 CPU program GET/PUT operation is automatically enabled in a V4.0 CPU.
However, a V4.0 CPU program GET/PUT operation in a V4.0 CPU is
not automatically
enabled. You must go the CPU "Device configuration", inspector window "Properties"tab,
"Protection" property to enable
GET/PUT access (Page 82).
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