User Manual

Easy to communicate between devices
7.8 S7 communication
Easy Book
Manual, 03/2014, A5E02486774-AF
153
7.8
S7 communication
7.8.1
GET and PUT instructions
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
read or write operation.
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).