Siemens SIMATIC S7-1200

Communication
11.2 PROFINET
S7-1200 Programmable controller
912 System Manual, V4.2, 09/2016, A5E02486680-AK
11.2.8.17
Common parameters for instructions
REQ input parameter
Many of the Open User Communication instructions use the REQ input to initiate the
operation on a low to high transition. The REQ input must be high (TRUE) for one execution
of an instruction, but the REQ input can remain TRUE for as long as desired. The instruction
does not initiate another operation until it has been executed with the REQ input FALSE so
that the instruction can reset the history state of the REQ input. This is required so that the
instruction can detect the low to high transition to initiate the next operation.
When you place one of these instructions in your program, STEP 7 prompts you to identify
the instance DB. Use a unique DB for each instruction call. This ensures that each
instruction properly handles inputs such as REQ.
ID input parameter
This is a reference to the "Local ID (hex)" on the "Network view" of "Devices and networks"
in STEP 7 and is the ID of the network that you want to use for this communication block.
The ID must be identical to the associated parameter ID in the local connection description.
DONE, NDR, ERROR, and STATUS output parameters
These instructions provide outputs describing the completion status:
Table 11- 49 Open User Communication instruction output parameters
Parameter
Data type
Default
Description
DONE Bool FALSE Is set TRUE for one execution to indicate that the last request
completed without errors; otherwise, FALSE.
NDR Bool FALSE Is set TRUE for one execution to indicate that the requested action
has completed without error and new data has been received;
otherwise, FALSE.
BUSY Bool FALSE Is set TRUE when active to indicate that:
• The job is not yet complete.
• A new job cannot be triggered.
Is set FALSE when job is complete.
ERROR Bool FALSE Is set TRUE for one execution to indicate that the last request
completed with errors, with the applicable error code in STATUS;
otherwise, FALSE.
STATUS Word 0 Result status:
• If the DONE or NDR bit is set, then STATUS is set to 0 or to an
informational code.
• If the ERROR bit is set, then STATUS is set to an error code.
• If none of the above bits are set, then the instruction returns
status results that describe the current state of the function.
STATUS retains its value for the duration of the execution of the
function.