22
Connections
12.6 Power supply, grounding, and shielding
The power supply terminal block is shown in the following figure.
3 conductors, minimum 1.5mm
2
wire diameter, minimum temperature conductor rating 105°C
NOTE
Make sure that the power supply has sufficient power capacity for the operation of the product.
The product must always be grounded to earth using a wire with a minimum diameter of 1.5mm
2
.
Grounding helps limit the effects of noise due to electromagnetic interference on the control system.
Earth connection will have to be done using either the screw or the faston terminal located near the
power supply terminal block. A label identifies the ground connection. Also ground the terminal 3 on
the power supply terminal block.
The power supply circuit may be floating or grounded. In the latter case, the power source common is
connected as indicated with a dashed line in the following figure.
When using the floating power scheme, note that internally the power common is connected to the
ground with a 1MΩ resistor in parallel with a 4.7nF capacitor.
The power supply must have double or reinforced insulation. The suggested wiring for the power sup-
ply is shown in the following figure.
All the electronic devices in the control system must be properly grounded. Grounding must be per-
formed according to applicable regulations.
Common M
L
M
L
1
2
3
+24V
L1
N
AC
DC
Panel
L M
