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CONNECTING TO EARTH GROUND
The third pin of the power connector of the G07 is chassis ground for the unit.
Your unit should be connected to earth ground (protective earth).
The chassis ground is not connected to signal common of the unit.
Maintaining isolation between earth ground and signal common is not required
to operate your unit. But, other equipment connected to this unit may require
isolation between signal common and earth ground.
To maintain isolation
between signal common and earth ground care must be taken when connections
are made to the unit.
For example, a power supply with isolation between its
signal common and earth ground must be used. Also, plugging in a USB cable
may connect signal common and earth ground.
1
1
USB’s shield may be connected to earth ground at the host. USB’s shield in
turn may also be connected to signal common.
POWER SUPPLY REQUIREMENTS
The Graphite panel requires a 24 VDC power supply. Your unit may draw
considerably less than the maximum rated power depending upon the features
being used. As additional features are used your unit will draw increasing
amounts of power. Items that could cause increases in current are modules,
additional on-board communications, SD card, and other features programmed
through Crimson.
To ensure you do not exceed the capacity of your Graphite host power supply,
calculate the total power consumption required for all of your planned modules.
Each module’s maximum power consumption is listed in the Specifications of
their Product Bulletin. The total power available for modules is listed in the
specifications of the Graphite host.
In any case, it is very important that the power supply is mounted correctly if
the unit is to operate reliably. Please take care to observe the following points:
– The power supply must be mounted close to the unit, with usually not more
than 6 feet (1.8 m) of cable between the supply and the operator interface.
Ideally, the shortest length possible should be used.
– The wire used to connect the operator interface’s power supply should be
at least 22-gage wire suitably rated for the temperatures of the environment
to which it is being installed. If a longer cable run is used, a heavier gage
wire should be used. The routing of the cable should be kept away from
large contactors, inverters, and other devices which may generate
significant electrical noise.
– A power supply with an NEC Class 2 or Limited Power Source (LPS) and
SELV rating is to be used. This type of power supply provides isolation to
accessible circuits from hazardous voltage levels generated by a mains
power supply due to single faults. SELV is an acronym for “safety extra-
low voltage.” Safety extra-low voltage circuits shall exhibit voltages safe
to touch both under normal operating conditions and after a single fault,
such as a breakdown of a layer of basic insulation or after the failure of a
single component has occurred. A suitable disconnect device shall be
provided by the end user.
EMC INSTALLATION GUIDELINES
Although Red Lion Controls Products are 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 a unit may be different
for various installations. Cable length, routing, and shield termination are very
important and can mean the difference between a successful or troublesome
installation. Listed are some EMI guidelines for a successful installation in an
industrial environment.
1. A unit should be mounted in a metal enclosure, which is properly connected
to protective earth.
2. Use shielded cables for all Signal and Control inputs. The shield 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 to earth ground (protective earth) at one end where the
unit is mounted.
b. Connect the shield to earth ground at both ends of the cable, usually when
the noise source frequency is over 1 MHz.
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. Also, 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. Long cable runs are more susceptible to EMI pickup than short cable runs.
5. In extremely high EMI environments, the use of external EMI suppression
devices such as Ferrite Suppression Cores for signal and control cables is
effective. The following EMI suppression devices (or equivalent) are
recommended:
Fair-Rite part number 0443167251 (RLC part number FCOR0000)
Line Filters for input power cables:
Schaffner # FN2010-1/07 (Red Lion Controls # LFIL0000)
6. To protect relay contacts that control inductive loads and to minimize radiated
and conducted noise (EMI), some type of contact protection network is
normally installed across the load, the contacts or both. The most effective
location is across the load.
a. Using a snubber, which is a resistor-capacitor (RC) network or metal oxide
varistor (MOV) across an AC inductive load is very effective at reducing
EMI and increasing relay contact life.
b. If a DC inductive load (such as a DC relay coil) is controlled by a transistor
switch, care must be taken not to exceed the breakdown voltage of the
transistor when the load is switched. One of the most effective ways is to
place a diode across the inductive load. Most RLC products with solid state
outputs have internal zener diode protection. However external diode
protection at the load is always a good design practice to limit EMI.
Although the use of a snubber or varistor could be used.
RLC part numbers: Snubber: SNUB0000
Varistor: ILS11500 or ILS23000
7. Care should be taken when connecting input and output devices to the
instrument. When a separate input and output common is provided, they
should not be mixed. Therefore a sensor common should NOT be connected
to an output common. This would cause EMI on the sensitive input common,
which could affect the instrument’s operation.
Visit RLC’s web site at http://www.redlion.net/emi for more information on
EMI guidelines, Safety and CE issues as they relate to Red Lion Controls
products.
I/O MODULE INSTALLATION
Modules must be installed beginning with slot 1 (left-most slot), with no
empty slots between the modules, and the order must match the modules order
in the Crimson database. Torque screws to 6.0 pound-force inch [96 ounce-force
inch] (0.68 N m).
REMOVE RUBBER
MODULE PLUG
WARNING: Disconnect all power
to the unit before installing or
removing modules.
The protective conductor terminal is bonded to conductive
parts of the equipment for safety purposes and must be
connected to an external protective earthing system.
Steps should be taken to eliminate the buildup of
electrostatic charges including but not limited to
connecting to earth ground.
