Isochronous Mode - Siemens SIMATIC ET 200S Operating Instructions Manual

4.2

Isochronous Mode

Note
For basic information on isochronous mode, refer to the Isochronous mode
(http://support.automation.siemens.com/WW/view/en/15218045) function manual.
Hardware Requirements
You will require the following for the 1SS in isochronous mode:
● A CPU that supports isochronous mode
● PROFIBUS master or PROFINET controller that supports the constant bus cycle time
● An IM 151 that supports isochronous mode
Features
Depending on the system parameter assignment, the 1SSI works in either non-isochronous
or isochronous mode.
In isochronous mode, the data communication between the master and 1SSI is isochronous
to the bus cycle.
In isochronous mode, all bytes of the feedback interface are consistent.
If isochronous mode fails, the feedback interface is not updated. In the user program, this
can be detected with the sign of life in the feedback interface.
Technological Functions
Operating Instructions, 06/2010, A5E00124867-07
1SSI
4.2 Isochronous Mode
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