West Control Solutions KS98-1 - Manual (Page 24)

I-6.3 RC protective circuitry
Load current free connections between the ground po-
tentials must be realized so that they are suitable both
for the low-frequency range (safety of persons, etc.)
and the high-frequency range (good EMC values). The
connections must be made with low impedance.
All metal grounds of the components installed in the
cabinet Ü or in the cabinet door * must be scre-
wed directly to the sheet-metal grounding plate to en-
sure good and durable contact.
In particular, this applies to earthing rails ä, protecti-
ve earth rail #, mountingplates for switching units
> and door earthing strips <.Controllers KS40/50/90
y and KS98-1 x are shown as an example for eart-
hing.
The max. length of connections is 20 cm (see relevant
operating instructions).
Generally, the yellow/green protective earth is
too long to provide a high-quality ground
connection for high-frequency interferences.
Braided copper cables Ö provide a high frequency
conducting, low-resistance ground connection, especi-
ally for connecting cabinet Ü and cabinet door *.
Because of the skin effect, the surface rather than the cross section is decisive for low impedance. All connections
must have large surfaces and good contact. Any lacquer on the connecting surfaces must be removed.
!
Due to better HF properties, zinc-plated mounting plates and compartment walls are more suitable for large-surface
grounding than chromated mounting plates.
I-6.4 Galvanic isolations
Galvanically isolated connection groups are marked by lines in the connecting diagram.
w Measuring and signal circuits: functional isolation up to a working voltage £ 33 VAC / 70 VDC against earth (to
DIN 61010-1; dashed lines).
w Mains supply circuits 90...250 VAC, 24 VUC: safety isolation between circuits and against earth up to a working
voltage
£ 300 Vr.m.s. (to EN 61010-1; full lines).
w Instruments with I/O extension modules (KS98-1xx-x3xxx and KS98-1xx-x4xxx): sockets 1-2 and 3-4 are galvani -
cally isolated from each other and from other signal inputs/outputs (functional isolation).
I-6.5 General connecting diagram
a
The max. permissible working voltage on input and signal circuits is 33 VAC / 70 VDC against earth ! Ot-
herwise, the circuits must be isolated and marked with warning label for “contact hazard”.
a
The max. permissible working voltage on mains supply circuits may be 250 VAC against earth and against
each other ! Only on versions with transmitter power supply (factory setting: connection across terminals
A12-A14)
a
Additionally, the units must be protected by fuses for a max. power consumption of 12,3VA/7,1W per in-
strument individually or in common (standard fuse ratings, min. 1A)!
Electrical connections - Safety hints 9499-040-82711
I-24 RC protective circuitry
A11
6
P3
y
x
ä
>
Ц
Ц
Ь
#
д
*
<
Fig. 8 Protective circuitry