Field Wiring; Wiring Guidelines; Avoiding Noise - Siemens SIMATIC 505 User Manual

2.4

Field Wiring

Wiring Guidelines

Avoiding Noise

2-8 Installing the Module
These modules do not require user-supplied power. A module consumes a
maximum of 2.0 W of +5 V power from the base backplane.
The modules have been designed to work with up to 1000 feet (303 meters)
of wire to the switch. The size of the wire used must be adequate for switch
current. To prevent noise on the signal wiring, keep signal and power wiring
separate. For input or output signals and class 2 power supply wires, use
shielded, twisted-pair cable (12–26 AWG or 0.16–3.2 mm
or solid-type).
Use supply wires suitable for at least 75 C. Signal wiring connected to this
module must be rated at least 300 V.
Wiring that does not meet the requirements could cause death and/or serious
injury or damage to equipment.
Ensure that your wire is suitable for at least 75 C, and that signal wiring con-
nected to this module is rated at least 300 V.
To minimize unwanted noise, follow these wiring installation guidelines.
Use the shortest possible wires.
Separate discrete and analog wires.
Avoid placing signal wires parallel to high-energy wires. If the two
must meet, cross them at right angles.
Avoid bending the wire into sharp angles.
Use wireways for wire routing.
When using shielded wires, ground them only at the source end for
better noise immunity.
Place wires so that they do not interfere with existing wiring.
Label the wires.
NOTE: Terminate shielding for the output cable at the same earth ground as
the user power supply. Terminate shielding for the input signal wire at the
same earth ground as the transmitter.
WARNING
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SIMATIC 505 Interrupt Input Module User Manual
2
, either stranded