Manufacturing AUTOMATION

Glossary Terms
Terms that are used on the Manufacturing Automation website


Universal Asynchronous Receiver/Transmitter. An interface device for serial/parallel conversion, buffering, and adding check bits.


Underwriters Laboratories, Inc. An independent laboratory that establishes standards for commercial and industrial products.

Unattended system (bar code)

A bar-code scanner/decoder combination that is triggered, or activated by an external source such as a computer, a programmable controller, or a switch operated automatically by some machine motion.


That condition which exists in a rotor when vibratory force or motion is imparted to its bearings as a result of centrifugal forces.

Unbalance Tolerance

The unbalance tolerance with respect to a radial plane (measuring plane or correction plane) is that amount of unbalance which is specified as the maximum below which the state of unbalance is considered acceptable.

Underflow bit

A bit that is set to indicate that the result of an operation is less than the minimum value that can be contained in a register.

Ungrounded Junction

A form of construction of a thermocouple probe where the hot or measuring junction is fully enclosed by and insulated from the sheath material.

Uni-directional I/O module

An I/O module whose communication with the scanner or processor is uni-directional and therefore uses only an input image area or an output image area.


(bar code) Universal Product Code. A standard bar code type for retail packaging in the United States.

Update time

1) For analog inputs, the time between updates to the memory in the analog module of the digital value representing the analog input signal. 2) For analog outputs, the time from the digital value being received at the analog module to when the analog output signal corresponds to that digital value.


In a manufacturing system, the passing of plant-floor information, such as production results, upward through the CIM hierarchy.

Upper nibble

The four most-significant bits of a byte.


An Uninterruptible Power Supply is used to ameliorate the effects of poor electrical power quality, including voltage anomalies, high-frequency noise, or ground loops. A UPS is especially applicable where power outages of over a half-second duration are possible.


Universal synchronous/asynchronous receiver/transmitter. A UART with the added capability for synchronous data communication.

Utility software

A program or routine, such as an editor or debugger, designed to perform a particular function of general usefulness.