Siemens SIMATIC ET 200S Operating Instructions Manual page 147

Isochrone mode:In isochrone mode, as well, the DO1 output is switched as soon as the
comparison condition is fulfilled and is therefore independent of the bus cycle.
Figure 3-13
Figure 3-14
Setting or Modifying the Function and Behavior of the Digital Output DO1
When setting or modifying the behavior of DO1, you must take all assignable
interdependencies into account. Failure to do so will generate a parameter assignment error
or a loading error.
Boundary conditions:
If you assign "Switch at Comparison Values" for DO1, you must:
• Set hysteresis = 0, and
• Assign "Output" for the DO2 output
Technological Functions
Operating Instructions, 02/2007, A5E00124867-05
V2 < V1 at the Start of Counting
V2 > V1 at the Start of Counting
1Count5V/500kHz
3.6 Count Modes
147