Siemens simatic s7-400 FM 450-1, User Manual, Page: 99 / 130

Encoder signals and their evaluation
9.5 Signal evaluation
Counter module FM 450-1
Manual, 02/2014, A5E03648739-02
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Input filters for the 24-V count inputs
For the purpose of suppressing interference, you can parameterize input filters with a
uniform filter time for the 24 V inputs A*, B* and N* and for the digital inputs. Input filters
available:
Table 9- 3 Input filters
Features Input filter 1
(default) Input filter 2
Typical input delay 1 µs 15 µs
Maximum count frequency 200 kHz 20 kHz
Minimum pulse width of count signals 2.5 µs 25 µs
Monitoring encoder signals
The 24-V count signals are not monitored to detect wire-breaks or short-circuits.
Coding plug (only for FM 350-1)
To operate this encoder, insert the coding plug in position D.