Siemens SIMATIC ET 200SP Manual page 31

The inputs are not electrically isolated from each other. The inputs are isolated against the
backplane bus.
Note
The RS422 signal standard offers greater interference immunity than the TTL signal
standard. If your incremental encoder or pulse encoder supports the RS422 and the TTL
signal standard, we recommend using the RS422 signal standard.
Input filter for RS422/TTL signals from incremental encoders and pulse encoders
To suppress interference, you can configure an input filter for the encoder inputs A, B and N.
The selected filter frequency is based on a pulse-break ratio of between 40:60 and 60:40.
This results in a specific minimum pulse/break time. Signal changes with a duration shorter
than the minimum pulse/break time are suppressed.
You can specify the following values for the filter frequency:
Table 3- 2
Filter frequency
100 Hz
200 Hz
500 Hz
1 kHz
2 kHz
5 kHz
10 kHz
20 kHz
50 kHz
100 kHz
200 kHz
500 kHz
1 MHz (default)
Digital inputs DI0 and DI1
Two digital outputs are available. The digital inputs are used for gate control, synchronization
and the Capture function. Alternatively, you can use one or both digital inputs without the
functions named and read the signal state of the respective digital input via the feedback
interface.
The digital inputs are not electrically isolated from each other.
Technology module TM PosInput 1 (6ES7138-6BA00-0BA0)
Manual, 04/2016, A5E33015755-AC
Filter frequency and respective minimum pulse/break time
Minimum pulse/break time
4.0 ms
2.0 ms
800 µs
400 µs
200 µs
80 µs
40 µs
20 µs
8.0 µs
4.0 µs
2.0 µs
0.8 µs
0.4 µs
Wiring
3.1 Pin assignment
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