Isochronous Mode - Siemens SIMATIC ET 200S Operating Instructions Manual

1Count24V

2.2 Isochronous mode

2.2 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 1Count24V in isochronous mode:
● A CPU that supports isochrone mode
● PROFIBUS master or PROFINET controller that supports the constant bus cycle time
● An IM 151 that supports isochrone mode
Features
Depending on the system parameter assignment, the 1Count24V works in either non-
isochronous or isochronous mode.
In isochronous mode, data communication between the bus master and 1Count24V is
isochronous to the cycle.
In isochronous mode, all 8 bytes / 12 bytes of the user data interface are consistent.
If a parameter assignment error occurs, the 1Count24V does not go into isochronous mode.
If isochronous mode fails due to faults or failure/delay of global control (GC), the 1Count24V
returns to isochronous mode during the next cycle without an error response.
If isochrone mode fails, the user data interface is not updated.
The T
12
/T overlap is supported by the module in firmware version V1.0.1 and later.
i o
Technological Functions
Operating Instructions, 06/2010, A5E00124867-07