Siemens SIMATIC ET 200SP System Manual

Basics of program execution
8.2 Asynchronous instructions
Distributed I/O system
148 System Manual, 09/2019, A5E03576849-AJ
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
The input parameter REQ starts the job to execute the asynchronous instruction.
②
The output parameter DONE indicates that the job was completed without error.
③
The output parameter BUSY indicates whether the job is currently being processed. When
BUSY =1, a resource is assigned for the asynchronous instruction. If BUSY = 0, then the re-
source is free.
④
The output parameter ERROR indicates that an error has occurred.
⑤
The output parameter STATUS/RET_VAL provides information on the status of the job execu-
tion. The output parameter STATUS/RET_VAL receives the error information after the occur-
rence of an error.
Figure 8-3 Block parameters of asynchronous instructions using the instructions WRREC and
CREATE_DB as examples.

Siemens SIMATIC ET 200SP Specifications

General

System Type	Distributed I/O System
Mounting	DIN Rail
Communication Protocol	PROFINET, PROFIBUS
IP Rating	IP20
Category	I/O Systems
Supply Voltage	24 V DC
Modularity	Yes
Hot Swapping	Yes
Storage Temperature	-40°C to +70°C
Digital Inputs	Yes
Digital Outputs	Yes
Analog Inputs	Yes
Analog Outputs	Yes
Communication Interface	PROFINET, PROFIBUS
Number of Modules	Up to 64
Relative Humidity	5 to 95% (non-condensing)
Operating Temperature	-25°C to +60°C