Siemens SIMATIC ET 200S Operating Instructions Manual page 51

Acknowledgment Principle in Isochronous Mode
In isochronous mode, exactly 4 bus cycles are always required to reset the status bits and to
accept values during the load function.
Figure 2-19
Error Detection
The program errors must be acknowledged. They have been detected by the 1Count24V
and are indicated at the feedback interface. Channel-specific diagnostics are performed if
you have enabled group diagnostics in your configuration (see device manual of the
interface module used).
The parameter assignment error bit is acknowledged by means of correct parameter
assignment.
Figure 2-20
In the case of continuous error acknowledgment (EXTF_ACK=1) or at CPU/Master Stop, the
1Count24V signals errors as soon as they are detected and resets them as soon as they
have been eliminated.
Technological Functions
Operating Instructions, 06/2010, A5E00124867-07
Acknowledgment Principle in Isochronous Mode
Error Acknowledgment
1Count24V
2.6 Count Modes
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