Siemens simatic s7-400 FM 450-1, User Manual, Page: 101 / 130

Encoder signals and their evaluation
9.5 Signal evaluation
Counter module FM 450-1
Manual, 02/2014, A5E03648739-02
101
Double evaluation
Double evaluation refers to the evaluation of the positive and negative edges of signal A.
The logic level at signal B determines the count direction, i.e. the up or down count pulse.
The diagram shows the double evaluation of signals:
Figure 9-5 Double evaluation
Quadruple evaluation
Quadruple evaluation refers to the evaluation of the positive and negative edges of signals A
and B. The logic level at the signals A and B determines the count direction, i.e. the up or
down count pulse.
The diagram shows quadruple evaluation of signals:
Figure 9-6 Quadruple evaluation
Default
Single evaluation is set by default.