Manufacturing AUTOMATION

Glossary Terms
Terms that are used on the Manufacturing Automation website

Ladder logic

symbolic representation illustrates schematically the functions of a
control circuit. The power lines form the sides of a ladder-like
structure, with the program elements arranged to form the rungs.


1. A time delay between the output of a signal and the response of the
instrument to which the signal is sent.
2. A time relationship between
two waveforms where a fixed reference point on one wave occurs after
the same point of the reference wave.


Local Area Network. A network that takes advantage of the proximity of
computers to offer relatively efficient, higher-speed communications
than long-haul or wide-area networks.


Link Access Protocol.


Light-Emitting Diodes are solid-state devices that radiate in the
visible region. They are used in alphanumeric displays and as indicator
or wiring lights.

Life Cycle

The minimum number of pressure cycles the transducer can endure and still remain within a specified tolerance.

Limit switch

an electromechanical device positioned to be actuated when a certain
motion limit occurs, thereby deactivating the actuator causing the

Limits of Error

A tolerance band for the thermal electric response of thermocouple wire
expressed in degrees or percentage defined by ANSI specification
MC-96.1 (1975).


said of any device or motion where the effect is exactly proportional to the cause.

Linear load

A predictable nonprocess energy load that has a profile that changes with time and condition.

Linear programming

A management technique applied to problems in which a linear function
of a number of variables is subject to a number of constraints in the
form of linear inequalities. Developed as a technique for planning the
diversified activities of the U.S. Air Force, the process generates
several different plans, requiring a criterion for deciding which plan
is best and how to find it. Mathematically, linear programming is the
analysis of problems in which a linear function of a number of
variables is to be maximized or minimized when those variables are
subject to a number of restraints in the form of linear inequalities.


The maximum deviation of the calibration curve from a straight line
between zero and full scale, expressed as a percent of full scale
output and measured on increasing measured only.

Load cell

a transducer for the measurement of force or weight. Action is based on strain gages mounted within the cell on a force beam.

Loop bandwith

Maximum rate at which a control loop can respond to a change in a
control parameter. It’s indicative of loop performance and is expressed
in Hertz (Hz).

Loop Resistance

The total resistance of a thermocouple circuit caused by the resistance
of the thermocouple wire. Usually used in reference to analog
pyrometers which have typical loop resistance requirements of 10 ohms.


Directing signals back toward the transmitting terminal at some point
along the communications path. Used as a method of troubleshooting.

LS-TTL Compatible

For digital input circuits, a logic 1 is obtained for inputs of 2.0 to
5.5 V which can source 20 µA, and a logic 0 is obtained for
inputs of 0 to 0.8 V which can sink 400 µA. For digital output
signals, a logic 1 is represented by 2.4 to 5.5 V with a current source
capability of at least 400 µA; and a logic 0 is represented by 0
to 0.6 V with a current sink capability of at least 16 MA. "LS" stands
for low-power Schottky.

LS-TTL Unit Load

A load with LS-TTL voltage levels, which will draw 20 µA for a logic 1 and -400 µA for a logic 0.