70 Electrical installation
Connecting the control cables to the RMIO board
Connect the control cables as described below. Connect the conductors to the
appropriate detachable terminals of the RMIO board (refer to
board (RMIO)
on page 75). Tighten the screws to secure the connection. Make 360-
degree EMC grounding at the cabinet entry in first environment installations. First
environment EMC compliance is defined in
(page 125).
Connecting the shield wires at the RMIO board
Strain relief
Double-shielded cable
Single-shielded cable: Twist the grounding wires of the outer shield and connect
them to the nearest grounding clamp.
Double-shielded cable: Connect the inner shields and the grounding wires of the
outer shield to the nearest grounding clamp.
Do not connect shields of different cables to the same grounding clamp.
Leave the other end of the shield unconnected or ground it indirectly via a few
nanofarads high-frequency capacitor (for example, 3.3 nF / 630 V). The shield can
also be grounded directly at both ends if they are
significant voltage drop between the end points.
Keep the signal wire pairs twisted as close to the terminals as possible. Twisting the
wire with its return wire reduces disturbances caused by inductive coupling.
Securing the control cables mechanically
Use strain relief clamps as shown above. Fasten the control cables to the cabinet
frame.
Compliance with EN 61800-3:2004
1
2
3
4
Insulation
Motor control and I/O
Strain relief
Single-shielded cable
in the same ground line
with no