Siemens SIMATIC ET 200SP System Manual

Basics of program execution
8.2 Asynchronous instructions
Distributed I/O system
146 System Manual, 09/2019, A5E03576849-AJ
Difference between synchronous/asynchronous instructions
The figure below shows the difference between processing an asynchronous instruction and
processing a synchronous instruction. In this figure the asynchronous instruction is called
five times before the execution is completed, for example, a data record is completely
transferred.
With a synchronous instruction, the instruction is fully executed in each call.
①
First call of the asynchronous instruction, start of processing
②
Intermediate call of asynchronous instruction, continuation of processing
③
Last call of the asynchronous instruction, termination of processing
④
The synchronous instruction is completely processed at each call
Duration of the complete processing
Figure 8-1 Difference between synchronous and asynchronous instructions

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