I/O Module Installation; Emc Installation Guidelines - red lion GRAPHITE G07C Manual

Graphite series operator interface terminals with plug-in i/o module capability

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Manual (12 pages)

Table of Contents

CONNECTING TO EARTH GROUND

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.

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.

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.