| ADSL |
Asymmetric Digital Subscriber Line |
| Analogue-to-Digital (A-D) Converter |
Used to produce digital output signals from an analogue
input. These may be control signals or alarm outputs |
| ASCII |
American Standard Code for Information Interchange.
Coding for text files
|
| Backbone |
The major multi-channel link in a network, from which
smaller links branch |
| Background noise |
Extraneous signals that might be confused with the
required measurement |
| Batch process |
Any process on which operations are carried out on
a limited number of articles, as opposed to continuous process |
| COM port |
A connection on a computer into which a serial device
may be plugged. |
| Data Acquisition |
The automatic collection of data from sensors, instruments
and devices
in a factory, laboratory or in the field |
| Device |
A peripheral which connects to the computer. Mice,
keyboards, printers,
data acquisition instruments, modules and cards are all devices |
| Digital-to-Analogue (D-A) Converter |
Used to produce analogue output signals. These may
be control signals or
synthesised waveforms |
| Analogue-to-Digital (A-D) Converter |
Used to produce digital output signals from an analogue
input. These may be control signals or alarm outputs |
| Dynamic Data Exchange (DDE) |
A standard Microsoft Windows protocol that defines
a way for Windows applications to share information with one another |
| Ethernet |
A local area network to which you can connect data
acquisition devices |
| GPRS |
Global Packet Radio
Services - upgrade of the GSM standard which uses
the same frequency range but allows data to transmitted in "packages".
With the 2.5G network transfer rates of about 40kbps are possible |
| GSM |
Global System for
Mobile Communications, one of the leading digital
cellular systems. GSM uses narrowband TDMA, which allows eight simultaneous
calls on the same radio frequency |
| HMI |
Human Machine Interface - The communication between
the computer system and the people who use it - Also known as man
machine interface |
| Input |
Data entering a device from the environment. A signal
being monitored by a data acquisition system |
| Interface |
A shared boundary. It might be a piece of hardware
used between two pieces of equipment, or a software display communicating
between the computer system and the people who use it |
| LAN |
Local area network - data communication system connecting
devices in the same vicinity. Data is transferred without the use
of public communications. Examples of LANs are Ethernet, token ring
and Modbus |
| Modbus |
An industrial networking system that uses peer-to-peer
communications. |
Multiplexing
|
Where each signal is switched in turn to a single
analogue-to-digital converter. As opposed to where one A-D converter
is used for each signal in simultaneous sampling. |
Network
|
The physical interconnection of devices sharing a
communications protocol |
| OEM |
Original Equipment
Manufacturer |
PCMCIA
|
Personal Computer Memory Card International Association
- credit card-sized plug-in cards for laptop computers |
Peer-to-Peer Communication
|
Communication between networked devices in which
any device can initiate data transfer. |
PID
|
Proportional gain, integral action time and derivative
action time. PID software, for example, compares an analogue input
value with a set point and if there's a discrepancy outputs an appropriate
analogue or digital control value, according the PID calculations. |
PLC
|
Programmable Logic Controller |
Port
|
The external connector on a device. |
Port Forwarding
|
|
Positive Temperature Coefficient
|
An increase in resistance due to an increase in temperature. |
Protocol
|
A set of rules used in data communications. |
| Pulse |
A temporary change in voltage of any length. |
Ramp Voltage
|
A steadily rising voltage. |
| Range |
The maximum and minimum allowable full-scale signal (input or
output).
|
Relay
|
Electromechanical device that opens or closes contacts when a
current is passed through a coil |
| Repeatability |
The ability of an instrument or system to give the same reading
under repeated identical conditions |
| Resolution |
A measure of the smallest change that can be detected. |
| RFID |
Radio Frequency Identification |
| RTU |
Remote Terminal Unit |
| SCADA |
Supervisory control and data acquisition - a large scale software
package usually used to monitor and control a manufacturing process.
They are degined to display and log information and alarms |
| Sensor |
Detects a change in a physical quantity (light, temperature or
pressure for example) and produce a corresponding electrical signal. |
| Serial Communication |
Data deing transferred one bit at a time. |
| Set Point |
Value of a controlled variable, departure from which causes a
controller to operate to reduce the error and restore the intended
steady state |
| Signal |
General term referring to a conveyor of information |
| Signal Conditioning |
Makes a signal suitable for input to an analogue-to-digital converter.
For example, a signal may be filtered to remove noise, or amplified
to meet the range of the A-D converter. |
| SMS |
Short Messaging Service - commonly known as a ‘text message.’
Each text message can comprise up to 160 characters which is transferred
from one mobile phone to another
|
| Surge |
A large, momentary, increase in the voltage on a power line |
| TCP/IP |
Transmission Control Protocol/Internet Protocol is the basic communication
language or protocol of the Internet. It can also be used as a communications
protocol in a private network (either an intranet or an extranet) |
| |
|
| Telemetry |
Remote measurement or the remote collection of data which can
be physical, environmental or biological. Telemetry is typically
used to gather data from distant or inaccessible locations |
| Text Message |
see SMS |
| Thermocouple |
Temperature sensor |
| Transducer |
A device which converts a physical quantity into an electrical
signal. Examples include thermocouples and photocells. Most sensors
are also transducers |
| Twisted Pair |
Cable that consists of individual wires wrapped around each other
for carrying telephone or computer data. Reduces pickup noise levels
in signals. |
| WAN |
Wide area network - a network of circuits spanning a large region
which is used to transmit data |
Wi-Fi
|
Wireless Fidelity - wireless communications network conforming
to IEEE 802.11 specifications |
| Zone |
An area of a building with independently controllable building
service provision. For efficiency zones should be separate where
occupancy, uncontrollable gains or losses of heat/chill or target
temperatures can be predicted to differ |
