Siemens SIMATIC S7-1500/ET 200MP System Manual page 215

Basics of program execution
9.2 Asynchronous instructions
Status of an asynchronous instruction
An asynchronous instruction shows its status via the block parameters STATUS/RET_VAL and
BUSY. Many asynchronous instructions also use the block parameters DONE and ERROR.
The figure below shows the two asynchronous instructions WRREC and CREATE_DB.
①
②
③
④
⑤
Figure 9-3
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The input parameter REQ starts the job to execute the asynchronous instruction.
The output parameter DONE indicates that the job was completed without error.
The output parameter BUSY indicates whether the job is currently being executed. When BUSY
=1, a resource is allocated for the asynchronous instruction. When BUSY = 0, the resource is
free.
The output parameter ERROR indicates that an error has occurred.
The output parameter STATUS/RET_VAL provides information on the status of the job execution.
The output parameter STATUS/RET_VAL receives the error information after the occurrence of
an error.
Block parameters of asynchronous instructions using the instructions WRREC and
CREATE_DB as examples.
Automation system
System Manual, 01/2023, A5E03461182-AK