Nexen TM340 912751 - Manual (Page 8)

5 FORM NO. L21279-B-0513
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
2).
• 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 3.9
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
Snubber applied across relay coil
3.3 WIRING INSTALLATION GUIDELINES
3. INSTALLATION (continued...)