Red Lion LEGEND - Manual (Page 53)

EMC COMPLIANCE INSTALLATION
This unit complies with the Electromagnetic Compatibility (EMC) standards
listed in the specifications. Compliance to the EMC standards was demonstrated
by means of a test set-up using the following installation methods:
1. Unit installed in a metal panel mounted to an open aluminum rack connected to
earth ground (protective earth).
2. Shielded (screened) cables for Signal and Control inputs, and solid state
outputs (03 & 04 SNK) with shield drain wire connected to earth ground at the
mounting panel only.
Multi-conductor Cable Function Used For
Belden #8451 - 2 conductor, #22 AWG
twisted pair w/ foil shield and drain wire
User Input 4/Inhibit
Belden #8771 - 3 conductor, #22 AWG
with foil shield and drain wire
Input A, Input B, User Inputs 1, 2 &
3, 03 & 04 SNK (solid state outputs)
Alpha #2404 - 4 conductor, #22 AWG
with foil shield and drain wire
RS485/RS232
Alpha #1173C - 3 conductor, #22 AWG
non-shielded
Relay Outputs
3. EMI line filter (Corcom #1VB3) placed on the DC power supply when DC
powered.
Test: EN 61000-4-4 EFT and ENV 50141 RF Conducted Immunity.
It should be noted that the methods listed above may not be necessary for every
unit installation. For the purpose of EMC testing, every input and output line on
the unit was connected with 25 feet (8 m) of cable. In extremely high EMI
environments, additional measures may be needed. The unit becomes more
immune to EMI with fewer I/O connections. Cable length, routing and shield
termination unit are very important and can mean the difference between a
successful installation or a troublesome installation.
ADDITIONAL EMC INSTALLATION GUIDELINES
Although this unit is designed with a high degree of immunity to
ElectroMagnetic Interference (EMI), proper installation and wiring methods
must be followed to ensure compatibility in each application. The type of the
electrical noise, source or coupling method into the unit may be different for
various installations. Listed below are some additional EMC guidelines for
successful installation in an industrial environment.
1. Use shielded (screened) cables for all Signal and Control inputs. The shield
(screen) pigtail connection should be made as short as possible. The
connection point for the shield depends somewhat upon the application.
Listed below are the recommended methods of connecting the shield, in order
of their effectiveness.
a. Connect the shield only at the panel where the unit is mounted to earth
ground (protective earth).
b. Connect the shield to earth ground at both ends of the cable, usually
when the noise source frequency is above 1 MHz.
c. Connect the shield to common of the unit and leave the other end of the
shield unconnected and insulated from earth ground.
2. Never run Signal or Control cables in the same conduit or raceway with AC
power lines, conductors feeding motors, solenoids, SCR controls, and heaters,
etc. The cables should be run in metal conduit that is properly grounded. This
is especially useful in applications where cable runs are long and portable
two-way radios are used in close proximity or if the installation is near a
commercial radio transmitter.
3. Signal or Control cables within an enclosure should be routed as far away as
possible from contactors, control relays, transformers, and other noisy
components.
4. In extremely high EMI environments, the use of external EMI suppression
devices, such as ferrite suppression cores, is effective. Install them on Signal
and Control cables as close to the unit as possible. Loop the cable through the
core several times or use multiple cores on each cable for additional protection.
Install line filters on the power input cable to the unit to suppress power line
interference. Install them near the power entry point of the enclosure. The
following EMI suppression devices (or equivalent) are recommended:
Ferrite Suppression Cores for signal and control cables:
Fair-Rite # 0443167251 (RLC #FCOR0000)
TDK # ZCAT3035-1330A
Steward #28B2029-0A0
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