Rockwell Automation 150 MNL/SMC DIALOG+/APP-PROD GUIDE - Manual (Page 191)

Glossary-4
Disable To inhibit logic from being activated.
Display That image that appears on a CRT screen or on other image projection systems.
Display Menu The list of displays from which you select specific information for viewing.
Duty Cycle The relationship between the operating and rest times or repeatable operation at
different loads.
Dynamic Braking See Braking.
Efficienc Ratio of mechanical output to electrical input indicated by a percentage. In motors,
it is the effectiveness with which a motor converts electrical energy into
mechanical energy.
EMF The initials of electromotive forc , which is another term for voltage or potential
difference. In DC adjustable speed drives, voltage applied to the motor armature
from a power supply is the EMF and the voltage generated by the motor is the
counter-EMF or CEMF.
Enable To allow an action or acceptance of data by applying an appropriate signal to th
appropriate input.
Enclosures Enclosure refers the housing in which the controller is mounted. Enclosures ar
available in designs for various environmental conditions.
• NEMA Type 1 – A general purpose enclosure of either a ventilated or a non
ventilated variety. It is used for most indoor applications and is intended to
protect against dust, light, indirect splashing and accidental human contact
with the electrical circuit.
• NEMA Type 3R – Intended for outdoor use, primarily to provide a degree of
protection against falling rain, and to be undamaged by the formation of ice on
the enclosure. It is not intended to provide protection against conditions such
as dust, internal condensation, or internal icing.
• NEMA Type 4 – A watertight enclosure is required whenever the unit is
subjected to a great amount of water from any angle. It is normally used in
areas that are repeatedly hosed down. These enclosures are not designed to be
submerged.
• NEMA Type 7 – An enclosure designed for a hazardous location, Class 1 (air)
Group D per the National Electrical Code. This hazardous environment is one
in which flammable gases or vapors are or may be present in the air in
quantities sufficient to produce explosive or ignitable mixtures. This enclosur
shall be of such substantial construction that it will withstand the internal
pressure resulting from explosions without bursting, permanently distorting o
loosening its joints.