Automating Manufacturing Systems - Process Control and ...

plc glossary - 35.11
DTR (Data Terminal Ready) - used as a data handshake in asynchronous communications to indicate a
listener is ready to receive data.
dump - a large block of memory is moved at once (as a sort of system snapshot).
duplex - serial communication that is in both directions between computers at the same time.
dynamic braking - a motor is used as a brake by connecting the windings to resistors. In effect the motor
becomes a generator, and the resistors dissipate the energy as heat.
dynamic variable - a variable with a value that is constantly changing.
dyne - a unit of force
35.5 E
EBCDIC (Extended Binary-Coded Decimal Information Code) - a code for representing keyboard and
control characters.
eccentric - two or more objects do not have a common center.
echo - a reflected sound wave.
ECMA (European Computer Manufacturer’s Associated) -
eddy currents - small currents that circulate in metals as currents flow in nearby conductors. Generally
unwanted.
EDIF (Electronic Design Interchange Format) - a standard to allow the interchange of graphics and data
between computers so that it may be changed, and modifications tracked.
EEPROM (Electrically Erasable Programmable Read Only Memory) -
effective sound pressure - the RMS pressure value gives the effective sound value for fluctuating pressure
values. This value is some fraction of the peak pressure value.
EIA (Electronic Industries Association) - A common industry standards group focusing on electrical
standards.
electro-optic isolator - uses optical emitter, and photo sensitive switches for electrical isolation.
electromagnetic - a broad range term reering to magnetic waves. This goes from low frequenc signals such
as AM radio, up to very high frequency waves such as light and X-rays.
electrostatic - devices that used trapped charge to apply forces and caused distribution. An example is
droplets of paint that have been electrically charged can be caused to disperse evenly over a
surface that is oppositely charged.
electrostatics discharge - a sudden release of static electric charge (in nongrounded systems). This can lead
to uncomfortable electrical shocks, or destruction of circuitry.
email (electronic mail) - refers to messages passed between computers on networks, that are sent from one
user to another. Almost any modern computer will support some for of email.
EMI (ElectroMagnetic Interference) - transient magnetic fields cause noise in other systems.
emulsify - to mix two materials that would not normally mix. for example an emulsifier can cause oil and
water to mix.
enable - a digital signal that allows a device to work.
encoding - a conversion between different data forms.
energize - to apply power to a circuit or component.
energy - the result of work. This concept underlies all of engineering. Energy is shaped, directed and focused
to perform tasks.
engineering work stations - are self contained computer graphics systems with a local CPU which can be
networked to larger computers if necessary. The engineering work station is capable of
performing engineering synthesis, analysis, and optimization operations locally. Work stations
typically have more than 1 MByte of RAM, and a high resolution screen greater than 512 by 512
pixels.
EOH (End of Header) - A code in a message header that marks the end of the header block.
EOT (End Of Transmission) - an ASCII code to indicate the end of a communications.
EPROM (Erasable Programmable Read Only Memory) - a memory type that can be programmed with