Siemens SIMATIC FM 452, Manual

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Wiring the FM 452 Electronic Cam Controller
4-5
FM 452 Electronic Cam Controller
C79000-G7076-C452-04
4.2 Wiring the Front Connector
Connecting Cords
•
The cords for digital inputs and digital outputs must be shielded if they exceed
certain lengths, as follows:
– digital inputs: cord length of more than 32 m
– digital ouputs: cord length of more than 100 m
•
The encoder cables must be shielded.
•
The shields of the encoder cables must make contact with the shield/protective
earth bar and the peripheral connector.
•
The cords A, A, B, B and N, N of the incremental encoder must be twisted in
pairs.
•
For the connecting cords, use flexible cord, cross-sectional area 0.25 to
1.5 mm
2
•
Ferrules are not necessary. If, however, you prefer to use them, you can use
ferrules without an insulation collar (DIN 46228, form A, short version) and two
cords each with 0.25 to 0.75 mm
2
in a ferrule.
Note
If you connect momentary-contact switches or proximity switches, you must use
shielded cords to achieve the optimum noise immunity.
Notes on 24 V DC Wiring
You connect the 24 V DC auxiliary supply for the encoders and digital outputs at
pins 36, 26 and 3.
Remember that all terminals 1L+ to 3L+ must be wired for the module to operate
error-free. You can use up to three power supplies.
Make sure that all the power supplies have a common chassis potential
(see Figure 4-1).
The absence of a voltage is indicated by a diagnostic event.
!
Caution
The module can be damaged.
If you connect the 24 V DC supply incorrectly, the module will be damaged and
must be replaced!
Make sure that the polarity of the 24 V DC supply is correct (auxiliary supplies
1L+, 2L+, 3L+ and chassis M).