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Appendix G Glossary

266 MODBUS® multivariable transmitter User manual 2105216 Rev. AB

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Term

Definition

bias

refers to adjusting the measurement to agree with the calibrated standard. This figure maybe either
positive or negative.

binary

abase-2 (instead of base-ten) numbering system. The binary digits are 0 and 1.

binary-coded decimal

a code for representing decimal digits in a binary format.

bit

one binary digit, either 0 or 1, which is the smallest unit of binary data. Used as an adjective, it may refer
to the number of bits used internally by a computer’s CPU or in a computer application (16 bit processor,
32 bit application). Also see

byte

bits per second

unit of rate for data transmission

board

the common name used to identify an electronic board. It is also called motherboard, engine card and
circuit board.

b/s, BPS

bits per second

buffer

1) a temporary storage device used to compensate for a difference in data rate and data flow between
two devices (typically a computer and a printer); also called a spooler. 2)an amplifier to increase the drive
capability, current or distance of an analog or digital signal

bus

a data path shared by many transmitters, for example a multipoint line with one or more conductors for
transmitting signals, data, or power

byte

a basic unit of information in computer storage and processing. A byte consists of 8 adjacent binary digits
(bits), each of which consists of a 0 or a 1.

cal checks

calibration checks

calibrate

to ascertain, usually by comparison with a standard, the locations at which scale or chart graduations
should be placed to correspond to a series of values of quantity which the instrument is to measure,
receive, or transmit. Also, to adjust the output of a transmitter, to bring it to a desired value within a
specified tolerance for a particular value of the input. And, to ascertain the error in the output of a
transmitter by checking it against a standard

central processing unit, CPU

the central part of a computer system that performs operations on data. In a personal computer the CPU
is typically a single microprocessor integrated circuit.

character

a letter, digit or other symbol that is used as the representation of data. A connected sequence of
characters is called a character string.

COMM

abbreviation for communication port

communication port, COMM

communication port (abbreviated COMM) refers to the Host computer's physical communication's port
used to communicate with peripheral equipment. The term is used by Totalflow when discussing local or
remote communication with various equipment including the XFC, FCU, XRC, RTU and LevelMaster.

CPU

central processing unit

differential pressure, DP

the pressure difference between two points in a system. For example, it is the difference in pressure
between the upstream and downstream taps of an orifice plate, used to measure volume passing
through the orifice.

digit

a measure of the display span of a panel meter. By convention, a full digit can assume any value from 0
through 9, a 1/2-digit will display a 1 and overload at 2, a 3/4-digit will display digits up to 3 and overload
at 4, etc. For example, a meter with a display span of ±3999 counts is said to be a 3-3/4 digit meter.

digital

a signal which has distinct states, either on or off (0 or 1). Digital computers process data as binary
information having either true or false states.

DIP switches

Dual In-line Package. A bank of switches typically used in setting the hardware configuration and base
address of an option card

flowing temperature, T

temperature of the flowing fluid, usually gas, and measured by an RTD.

flowing, DP

differential pressure of the flowing fluid, usually gas. See

differential pressure

for more information.

Factory Mutual Research Corporation is an organization which sets industrial safety standards.

gauge pressure

absolute pressure minus local atmospheric pressure

HMI