Glossary of Terms

Glossary of Terms for the Scale Industry

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Range
The operating range of a device is a statement of the limits in which it can function effectively. The operating range of a sensor is usually specified as the lowest and highest input values which it is capable of measuring.

Other ranges are frequently quoted on device specifications, for example temperature range refers to the maximum and minimum temperatures in which the device will work. Humidity and pressure ranges are also commonly quoted.

It is important not to exceed these ranges because not only may the device fail to operate effectively, it could also damage other components of the system or even be a risk to health and safety.

Rated Load
Value of load that is considered to be '100%' loading on transducer by manufacturer of measuring equipment, not user.

Note: Rated load can be made up of any combination of live and dead loads, and sum of live and dead loads can exceed rated load.

Rating
The rating of a device relates to the recommended conditions, electrical or mechanical, under which it will successfully or safely operate. A description of the type of rating is usually given, for example maximum temperature rating, or average load rating.

Recording Instrument
Measuring instrument in which values of measured quantity are recorded.

Reliability
The reliability of a device is similar to its operating life, and may often be quoted instead, depending on its nature. Reliability is the ability of a device to perform its function under specified conditions for a stated period of time, or a stated number of operations, whilst remaining within its specification.

Repeatability
Repeatability is a numerical measurement of precision under fixed conditions. It is a measurement of the ability of a device to produce identical indications or responses, for repeated applications of the same value of the physical quantity to be measured. It may be given as ± a maximum percentage of the reading, or within stated limits of each reading.

Note: Expressed as maximum non-repeatability in percent of span. Does not include hysteresis. Reproducibility is another term for repeatability.

Reproducibility
Closeness of agreement among repeated measurements of output for same value of input made under same operating conditions over period of time, approaching from either direction.

Note: 1) Expressed as maximum non-reproducibility in percent of span for specified time. Normally, this implies long period of time, but under certain conditions, may be short time during which drift may not be included. 2) Includes hysteresis, drift, repeatability, and dead band. 3) Operating conditions and input may vary between normal operating limits between measurements.

Resolution
The resolution with which a device senses or displays a value relates to the smallest input or change in input it is able to detect. It is usually expressed in terms of the smallest increment, which can be measured or sensed.

The higher the resolution of a display, the smaller the increment it is able to measure. For example, a five-digit display, which can measure a quantity to 0.0001 units, has a higher resolution than a four-digit display measuring to 0.001 units. It is usually expressed as a percentage.

Note: Resolution is termed fine or coarse as interval is small or large.

Response
The response of a device is the time it takes to reach its final output value for a given input. It may be quoted in terms of seconds or fractions of a second, or sometimes as a percentage of its full value. For example, if a specification states that 95% response time is 3 seconds, it means that the device takes 3 seconds to reach 95% of its final output value.

Response Time
Time required for system to readjust from one set of defined conditions to another set of defined conditions.

RFI
Radio-frequency interference. Radio-frequency energy of sufficient magnitude to have possible influence on operation of other electronic equipment. Often caused by improper grounding, plasma, and unsuppressed inductive loads switched by hard contacts.

ROM
Read Only Memory. Type of memory with data content that cannot be changed in normal mode of operation. In use, bits and words are read on demand, but not changed.

RS-232-C
EIA standard that specifies electrical, mechanical, and functional characteristics for serial binary communication circuits in point-to-point link. Limited range of few feet.

RS-422
EIA standard that specifies electrical characteristics of balanced-voltage digital interface circuits in point-topoint link. Range of several thousand feet.

RS-485
EIA standard that specifies electrical characteristics of balanced-voltage digital interface circuits in multi-point link. Range of several thousand feet.

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