MTL700 SERIES
Shunt-diode Safety Barriers
For safe measurement and control
in hazardous areas
- 1 or 2 channels in same slim
package
- Electronic protection prevents
blown fuses
- All models short-circuit proof
- Stay-put tagging & cable-screen
earthing
- Certified to worldwide standards
MTL700 Series Shunt-Diode
Safety Barriers are 1-
or 2-channel devices which pass an electrical signal in either direction
without shunting it, but limit the transfer of energy to a level
that cannot ignite explosive atmospheres. Connected in series with
the signal transmission lines on a process plant, they protect hazardous-area
wiring and equipment against faults occurring in the safe area,
and enable a wide range of measurement and control operations to
be carried out simply and inexpensively by intrinsically safe techniques.
Conventional wiring and, frequently, standard transducers can be
employed in the hazardous area, and can be worked on for maintenance
or calibration purposes without further precautions. Safe-area equipment
needs no certification and can be modified or extended as required.
Applications include the protection
of installations containing 'simple' uncertified devices such as
thermocouples, switches, and resistive sensors, or separately certified
'energy storing' or 'voltage producing' apparatus, for example ac
sensors, transmitters, and current-to-pneumatic (I/P) converters.
All 'simple' devices can be used in areas of continuous hazard:
'energy-storing apparatus' is certified for use in a particular
'zone' or 'division'. MTL700 Series barriers give protection in
all normally occurring explosive atmospheres, including all mixtures
with air of flammable gases, vapours, dusts, fibres and flyings.
Essential features
of the MTL700 Series are the self checking 'as-you-mount-it' earthing
via two studs directly to nickel-plated brass or copper busbar.
The earth connection is on top of the unit, allowing easy inspection,
installation and removal. The shape of the barrier has been designed
for easy wiring, while the common (14.5 mm) space requirement of
both 1- and 2-channel units simplifies planning or alteration of
installations of all sizes. The terminals of the barrier are angled
for easy access and accept field wiring directly, making a second
set of terminals unnecessary. The busbar is insulated for separate
earthing, to eliminate the danger of invasion by fault currents.
The range was tailored to meet
most users' needs without offering a confusing mass of options.
Following the philosophy that users are busy people deserving clear
solutions, we have highlighted throughout the literature the 7 'key'
application-oriented barriers that meet the majority of process
control requirements. These key barriers are stocked worldwide and
are available from MTL distributors on immediate delivery, enabling
users to reduce their inventory and making the choice and use of
barriers even easier.
Overvolt protection in four models
permits their use with unregulated power supplies.
For higher-power applications,
a range of MTL700P barriers takes advantage of changes in interpretation
of the standards.
Data Sheet
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