Elettronica Santerno SINUS/ISD 200 S-0.75, Руководство пользователя, Страница: 18 / 206

15P0082B8
USER MANUAL
SINUS/ISD
3 - 4/14
3.1.4.2 Star Point Earthing
A star-point earthing policy separates `noisy’ and `clean’ earths. Four separate earth busbars (three are
insulated from the mounting panel) connect to a single earth point (star point) near the incoming safety earth
from the main supply. Flexible, large cross-section cable is used to ensure a low HF impedance. Busbars are
arranged so that connection to the single earth point is as short as possible.
PLC
PE PE
PE
0D 0D
0D 0D
0A 0A
0A
Doors
Metal
Work
110V
Control
24V Control
unscreened signals
STAR POINT
Incoming Safety Earth (PE)
to motor to motor to motor
screened screened
PE
Analogue Clean Earth
Dirty Earth
Digital Clean Earth
VSD VSD
VSD
Signal/Control Screen
all screened signals not
f
Back Panel
U-clip used to terminate screen
connection to the back panel
PE = Protective Earth
0A = 0 Volts Analogue
0D = 0 Volts Digital
f = External Filter
VSD = Variable Speed Drive
PLC = Programmable Logic Controller
going directly to a VSD
Metal Work Earth
Back
Panel
PE PE PE
1 Clean Earth Busbar (insulated from the mounting panel)
Used as a reference point for all signal and control cabling. This may be further subdivided into an analogue and
a digital reference busbar, each separately connected to the star earthing point. The digital reference is also
used for any 24V control.
2 Dirty Earth Busbar (insulated from the mounting panel)
Used for all power earths, i.e. protective earth connection. It is also used as a reference for any 110 or 220V
control used, and for the control transformer screen.
3 Metal Work Earth Busbar
The back panel is used as this earth busbar, and should provide earthing points for all parts of the cubicle
including panels and doors. This busbar is also used for power screened cables which terminate near to (10cm)
or directly into a VSD - such as motor cables, braking choppers and their resistors, or between VSDs - refer to
the appropriate product manual to identify these. Use U-clips to clamp the screened cables to the back panel to
ensure optimim HF connection.
4 Signal/Control Screen Earth Busbar (insulated from the mounting panel)
Used for signal/control screened cables which do not do not go directly to the VSD. Place this busbar as close as
possible to the point of cable entry. `U’ clamp the screened cables to the busbars to ensure an optimum HF
connection.
Figure 3-2 Star Point Earthing Figure 3-2 Star Point Earthing