Ttl Encoder Signals - Siemens SIMATIC S7-1500 Manual

Wiring

3.3 TTL encoder signals

3.3 TTL encoder signals
TTL encoder signals/counting signals
The TM PosInput 2 can process encoder signals that use the TTL signal standard. The
counting encoder signals are designated with the letters A, B and N. An encoder signal with
TTL standard uses a single cable.
You can connect the following encoder types:
● TTL incremental encoder with N signal:
The encoder signals A, B and N are connected using the correspondingly marked
terminals. A and B are the two incremental signals phase-shifted by 90°. N is the zero
mark signal that supplies one pulse per revolution.
● TTL incremental encoder without N signal:
The encoder signals A and B are connected using the correspondingly marked terminals.
A and B are the two incremental signals phase-shifted by 90°. The N terminal remains
unconnected.
● TTL pulse encoder without direction signal:
The counting signal is connected to the A terminal. The count direction can be specified
via the control interface. The B and N terminals remain unconnected.
● TTL pulse encoder with direction signal:
The counting signal is connected to the A terminal. The direction signal is connected to
the B terminal. Counting down takes place at a high level of the direction signal. The N
terminal remains unconnected.
● TTL pulse encoder with up/down counting signal
The up counting signal is connected to the A terminal. The down counting signal is
connected to the B terminal. The N terminal remains unconnected.
The inputs are not isolated from each other. The inputs are isolated from 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.
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Technology module TM PosInput 2 (6ES7551-1AB00-0AB0)
Manual, 06/2018, A5E03982218-AB