Siemens SIMATIC ET 200S Operating Instructions Manual page 223

Double Evaluation
Double evaluation means that the positive and negative edge of the A signal are evaluated.
Whether up or down count pulses are generated depends on the level of the B signal.
The diagram below illustrates the double evaluation of the signals.
Figure 3-46
Quadruple Evaluation
Quadruple evaluation means that the positive and negative edges of the A and B signals are
evaluated. Whether up or down count pulses are generated depends on the levels of the A
and B signals.
The diagram below illustrates the quadruple evaluation of the signals.
Figure 3-47
Note
A counting frequency of 500 KHz refers to the maximum frequency of the A and B signals.
With double evaluation, a maximum frequency of 1 MHz is produced for the counting pulses;
with quadruple evaluation, the maximum frequency is 2 MHz.
Technological Functions
Operating Instructions, 06/2010, A5E00124867-07
Double Evaluation
Quadruple Evaluation
3.10 Evaluation of count and direction signal
1Count5V
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