Siemens SIMATIC ET 200S Operating Instructions Manual page 102

1Count24V/100kHz
2.8 Position Detection
Note
Only one of the following control bits can be set at a particular time:
LOAD_VAL or LOAD_PREPARE.
Otherwise, the ERR_LOAD error is reported until all the specified control bits are deleted
again.
The ERR_LOAD error bit is only deleted when a correct value is transferred as follows.
Acknowledgment Principle in Isochrone Mode
In isochrone mode, exactly 4 or 6 bus cycles are always required to reset the status bits and
to accept values during the load function.
Figure 2-42
102
Acknowledgment Principle in Isochrone Mode
Technological Functions
Operating Instructions, 02/2007, A5E00124867-05