Nexen TC920V 964356 - Manual (Page 9)

6 FORM NO. L21268-C-1013
3.2 WIRING INSTALLATION GUIDELINES
This product is designed to minimize the effects of ElectroMagnetic Interference (EMI) on its operation, but as
with any electronic device, proper installation and wiring methods are necessary to ensure proper operation. By
doing so, the interference from external effects such as electrical line spikes, electrical noise, static electricity, etc.
will be minimized. The following methods outline wiring installation guidelines to protect your system:
• All input and output signal and sensor cables must
be shielded with the shields tied to earth ground at
one end. In case of very high frequency (MHz range)
electrical noise, both ends of the shield need to be
tied to earth ground.
• Keep cable length and unshielded leads as short as
possible. Think of them as antennae for noise.
• Use power line filters to suppress interference on
the AC voltage lines that power the unit.
• Place a resistor-capacitor network (snubber) across
inductive coils such as relays and solenoids in order
to stop electrical interference at the source (See
Figure 3.4).
• Isolate signal and sensor cables from cables
carrying AC voltages, power for high current loads
or relays and solenoids. Either relocate the signal
and sensor cables away from other cables or use
grounded metal conduits to shield them. This will
reduce the potential for noise interference between
the signal and sensor cables and the other noisy
cables.
FIGURE 3.4
Snubber Applied Across Relay Coil
For environments that experience high levels of static
electricity follow these additional guidelines:
• Remove the static charge from material carrying it.
In the case of webs that carry static charges, there
are static charge removal products available such as
static bars and ionized blowers.
• Ensure that sensors and machine frames are
grounded to earth through a low impedance path.
• Wrap grounding tinsel around sensors and cables
that are close to the source of the static electricity
and ground the tinsel to earth.
• Tie all signal and sensor cable shields directly
to earth ground without passing through the
electronic device. This will help prevent high voltage
interference from coupling into other circuits within
the device.
Relay
R
C
Snubber
3. INSTALLATION (continued...)