UM-0085-B09
DT80 Range User Manual
Page 403
RG
Glossary
4–20mA loop
A common industrial measurement standard. A transmitter controls a current in the range of 4 to 20mA as a function
of a measurement parameter. Any receiver(s) or indicator(s) placed in series can output a reading of the parameter.
Main advantage is 2-wire connection and high immunity to noise pick-up. Usually powered from a 24V supply.
50/ 60Hz rejection
The most common source of noise is that induced by AC power cables. This noise is periodic at the line frequency.
DT80s are able to reject most of this noise by integrating the input for exactly one line cycle period (20.0 or 16.7ms).
Ω
Ohm, a unit of resistance
µA
Microampere, 10
-6
A
µs
Microsecond, 10
-6
s
µStrain
Micro strain, strain expressed in parts per million (ppm). Strain is a measure of the stress-induced change in length
of a body.
µV
Microvolt, 10
-6
V
A
Ampere or amp, a basic unit of electrical current
actuator
A device that converts a voltage or current input into a mechanical output.
ADC
Analog-to-Digital Converter. Part of the DT80’s input circuitry that converts an analog input voltage to a digital
number (in other words, it converts a smoothly-varying signal to a quantised digital value). The DT80 is a digital
instrument, and therefore requires an ADC to convert analog sensor signals into digital form prior to processing.
Important characteristics of an ADC are its linearity, resolution, noise rejection and speed.
Ah
Ampere-hour, a unit of electrical charge, often used when referring to battery capacity
analog
a quantity that can vary continuously through a potentially infinite number of values — for example, the time swept
out by the hands of a clock, or the output of a thermocouple. Compare with digital.
analog ground
Reference point for the DT80's instrumentation amplifier. This ground is normally isolated from any other ground
point so it can "float" up or down to match the common mode voltage of the input. This isolation extends the DT80's
common mode voltage limits, and helps prevent ground loops.
ASCII
American Standard Code for Information Interchange. A coding system designed for standardising data transmission
to achieve hardware and software compatibility. It assigns a 7-bit code to each of the 128 standard characters: 96
visible characters — letters, numbers and punctuation marks (including the space character); 32 hardware control
characters — sounding a bell, advancing a printer page, carriage return, line feed and so on.
Asynchronous
Not synchronised, not occurring at pre-determined or regular intervals. A telephone conversation is asynchronous
because both parties can talk whenever they like. In an asynchronous communications channel, data is transmitted
intermittently rather than in a constant stream.
Auto-IP
A system where a device on a TCP/IP network can, in the absence of a DHCP server, automatically select its own
IP address and other network parameters.
