Siemens simatic s7-400 FM 450-1 - Page 32

Wiring
4.4 Module status after power is switched on
Counter module FM 450-1
32 Manual, 02/2014, A5E03648739-02
5.2 VDC encoder power supply
The module generates a 5.2 VDC voltage from the 1L+/1M auxiliary voltage at a maximum
current of 300mA per count channel; this voltage is available on the respective "DC5.2V"
terminal to supply a 5 V encoder with short circuit-proof voltage.
24 VDC encoder power supply
1l+/1M voltage is provided on output "24 VDC" to supply an encoder with short circuit-proof
24-V voltage. The encoder power supply is short-circuit checked.
5 V encoder signals A and /A, B and /B, N and /N
You can connect incremental encoders with 5 V differential signals in compliance with
RS422, i.e. incremental encoders with the differential signals A and /A, B and /B, N and /N.
The A and /A, B and /B, N and /N signals are connected via the correspondingly labeled
terminals
The signals N and /N are only to be connected if you wish to set the counter to the zero mark
of the encoder.
The inputs are not electrically isolated from the S7-400 bus.
24-V encoder signals A*, B* and N*
24 V signals are identified with the letters A*, B* and N*.
You can connect three different types of encoders to each counter:
● Incremental encoders with 24- V signals:
The signals A*, B* and N* are connected via the correspondingly labeled pins.
● Pulse encoders without directional level:
The signal is connected to terminal A*
● Pulse encoders with directional level:
The count signal is connected to the terminal A*. The directional level is connected to
terminal B*.
The inputs are not electrically isolated toward the S7-400 bus.