5
EMC INSTALLATION GUIDELINES
Although this controller is designed with a high degree of
immunity to Electromagnetic Interference (EMI), proper installation
and wiring methods must be followed to ensure electromagnetic
compatibility (EMC) in each application. The type of the electrical
noise, source or coupling method into the controller may be
different for various installations. The controller becomes more
immune to EMI with fewer I/O connections. Cable length, routing,
and shield termination are very important and can mean the
difference between a successful or troublesome installation. Listed
are some EMC guidelines for successful installation in an industrial
environment.
1. The controller should be mounted in a metal enclosure that is
properly connected to protective earth.
2. 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 controller 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 more than 1 MHz.
c. Connect the shield to common of the controller and leave the
other end of the shield unconnected and insulated from earth
ground.
3. 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 through 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.
4. Signal or Control cables within an enclosure should be routed as
far away as possible from contactors, control relays,
transformers, and other noisy components.
5. 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 controller 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
controller 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 (Red Lion Controls # FCOR0000)
TDK # ZCAT3035-1330A
Steward # 28B2029-0A0
Line Filters for input power cables:
Schaffner # FN610-1/07 (Red Lion Controls # LFIL0000)
Schaffner # FN670-1.8/07
Corcom # 1 VR3
Note: Reference manufacturer’s instructions when installing a
line filter.
6. Long cable runs are more susceptible to EMI pickup than short
cable runs. Therefore, keep cable runs as short as possible.
7. Switching of inductive loads produces high EMI. Use of snubbers
across inductive loads suppresses EMI.
Snubber: Red Lion Controls # SNUB0000.
STEP 1 Setting The Jumpers (Analog output models only)
To insure proper operation, the Analog Output jumpers must be set
to the same range selected in programming Module 2-OP. The
default jumper setting is for 20 mA. The default setting in Module
2-OP is 4-20 mA. To access the jumpers, insert a flat-blade
screwdriver between the front panel and the side case slot. This
should disengage the top and bottom front panel latches from the
case grooves. Pull the front panel assembly with the controller boards
out of the case. The jumpers are located inside the controller on the
left board along the back top section.
VIEW FROM TOP OF UNIT
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