Siemens FM 450-1 - Page 82

in additional, you can wire a signal for direction detection to terminal B* of the relevant counter.
If your encoder does not return a corresponding signal, you can wire a corresponding ID signal
you generate within the user program, or use a corresponding process signal.
The diagram shows the time pro󹪝le of the encoder signals, and the resultant count pulses
Signal A*
Signal B *
as direction
level
Up count
pulses
Down count
pulses
Up
Down
Figure 9-3 Signals of a 24-V pulse generator with direction signal
Programming the encoder inputs
The count direction is de󹪝ned by programming the encoder inputs. The diagram shows a change
of the count direction based on parameter settings.
Table 9-2 Count direction determined by input parameters
Programming Terminal B* Count direction
current sourcing, push-pull not wired Up
24 V connected Down
current sinking not wired Down
Short-circuited to ground Up
Set the "24 V pulse and direction" parameter for the selected encoder.
You can not reverse the direction of these count signal by inverting the B* signal.
Note
This type of evaluation may cause the count value to "drift o󹪜" at the edges if count signal
oscillates, as all signals are added.
Encoder signals and their evaluation
9.4 24-V signals
Counter module FM 450-1
82 Equipment Manual, 03/2022, A5E03648739-AC