|
ADC |
Analogue to Digital
Convertor |
|
AI |
Artificial Intelligence
|
|
Algorithms |
Algorithms are routines
to deal with particular
situations; for example,
a controller formula to
correct an element in a
continuous process. |
|
Analogue |
Analogue devices are those
which communicate via a
small electric current.
For example, food industry
flow meters send a current
of between 4mA to 20mA.
The lowest value would represent
no flow at all; the largest
would indicate maximum flow.
|
|
ANN |
An abbreviation sometimes
used for artificial
neural networks.
|
|
ANSI |
American National
Standards Institute.
|
|
APC |
Advanced Process
Control. This includes
continuous applications
such as cracking towers
and advanced batch control
involving activities like
blend ratio control or bleaching.
|
|
BMS |
Building Management
System |
|
CAD |
Computer Aided
Design. This may
allow designers to manipulate
parts drawings and simulate
processes. |
|
CAM |
Computer Aided
Manufacturing is
a generic term for systems
help manufacturing. They
include CNC and process
control. |
|
CIM |
Computer Integrated
Manufacturing is
a term used to describe
an operation which makes
all or most of its information
available through a fully
integrated data management
network. The object is to
increase efficiency by integrating
all the facility's data
management systems. |
|
Closed Systems |
See open systems. Closed
systems are the opposite
to open systems. In other
words, they are proprietary.
|
|
CNC |
Computer Numerical
Control allows machines
to be operated from PLCs
by means of a numerical
code. |
|
Console |
A console is the term for
the actual screen and keyboard
used in the work stations.
|
|
Controller |
A device which controls
another machine in the process
directly, usually being
wired to it directly. |
|
DAC |
Digital to Analogue
Convertor |
|
DCS |
A Distributed Control System
is designed to have a series
of decentralised control
centres which have some
degree of autonomy, but
are still integrated into
a whole system (except in
an emergency shutdown).
The centre has hierarchical
control over the rest, but
most control takes place
away from the centre. |
|
DDE |
Direct Digital
Embedding. |
|
Digital |
Digital devices transmit
in bits, i.e. a series of
binary numbers, to other
parts of the system. |
|
Discrete Process |
A process handling distinct,
separate products. The usual
example is an automotive
factory product line, where
each car is a distinct artefact.
Discrete processes are in
contradistinction to continuous
processes handling liquids.
|
|
ERP |
Enterprise Resource
Planning. |
|
ESD |
Emergency Shut
Down. |
|
EWS |
Engineering Work
Station |
|
Expert Systems |
See Knowledge Based Systems
(KBS). |
|
Fault Tolerant |
Fault tolerant architecture
allows the system to continue
working even when part of
the system fails. This is
usually done by having multiple
components running in parallel;
when one part fails the
redundant devices can take
over, allowing engineers
to repair the system without
disrupting the process.
|
|
FCU |
Field Control
Unit. |
|
FDDI |
A Fibre Distributed
Data Interface
is a type of LAN. |
|
FF |
Fieldbus Foundation.
|
|
Fieldbus |
Fieldbus is a generic term
used to describe a common
communications protocol
for control systems and/or
field instruments. Although
some standard forms have
been agreed for instruments,
the DCS industry as a whole
have so far no agreed fieldbus.
Often, the Foundation Fieldbus
is referred to simply as
the Fieldbus. |
|
Function Block |
Smart devices on a fieldbus
are capable of operating
independently. The microprocessors
which store control software
are the function blocks.
They are particular to an
application. |
|
Fuzzy Logic |
Fuzzy logic is designed
for situations where information
is inexact and traditional
digital on/off decisions
are not possible. It divides
data into vague categories
such as "hot", "medium"
and "cold". |
|
Gas Chromatagraphs |
Gas chromatagraphs are used
to analyse the make up of
a gas at various points
in the process. It has been
suggested that neural networks
might be used to replace
their functions in some
circumstances at much lower
cost. |
|
Genetic Algorithms (Gas)
|
These are routines which
are capable of self adaption.
As with neural networks,
they are based on an analogy
with nature; in this case
the best algorithms breed
with each other to provide
new variants in a "survival
of the fittest". As yet
this cutting edge technology
is not widely used in process
control. |
|
GOT |
Graphic Operator
Terminal. A kind
of HMI. |
|
Granule |
An information granule is
a term used by some fuzzy
logic experts to describe
a fuzzy set of objects which
can be seen as a unit in
fuzzy logic calculations.
|
|
GUI |
The standard abbreviation
for Graphic User
Interface; this is
an interface which uses
graphics rather than characters
to communicate. |
|
GUS |
Global User
Station |
|
HMI |
Human Machine
Interface. Sometimes
these are called Man Machine
Interface. See MMI.
|
|
HVAC |
Heating, Ventilation
and Air Conditioning.
|
|
ICS |
An Information and
Command Station
is used by operators to
control and monitor the
plant's processes. |
|
IEC |
International Electrotechnical
Commission. |
|
IFC |
International Fieldbus
Consortium. An hybrid
body formed from the IFG
and the OFC in 1990. It
voted to stop work after
the FF was created in 1994.
|
|
IFG |
International Fieldbus
Group |
|
ILD |
Instrument Loop
Diagram. A drawing
showing the connections
from the field device all
the way through to the system
terminations. |
|
IMC |
Institute of Measurement
and Control. InstMC. |
|
Interchangability |
Interchangability is the
ability, in an open system,
to swap instruments on a
network without losing functionality.
|
|
Interoperability |
Interoperability is the
ability to plug instruments
or other elements produced
by more than one manufacturer
into a fieldbus network
and still have them able
to communicate with each
other and the control system(s).
They may, however, have
different levels of functionality.
|
|
I/O Module |
An Input/Output module,
which usually contains several
I/O points. |
|
I/O point |
An Input/Output point, used
as a connection point. |
|
ISA |
Instrument Society of America.
|
|
ISP |
This is the standard abbreviation
for the Interoperable
Systems Project,
which a number of companies
are hoping will produce
an international fieldbus.
The main industry backers
are Fisher-Rosemount, Yokogawa
and Siemens. |
|
JIT |
Just In Time.
A manufacturing process
that produces products just
in time to meet orders,
not for stock. |
|
KBS |
A Knowledge Based
System is a system
which attempts to use a
database to solve problems
by inference. These are
sometimes called expert
systems. |
|
LAN
|
Local
Area Networks
are used to link up computers.
The best known protocol
for LANs is Ethernet.
|
|
LonWorks |
Local Operating Networks
is another fieldbus, used
by about 2,000 companies.
The chips are made by Toshiba
and Motorola for the German
Echelon. They are then sold
onto to various manufacturers.
|
|
Loop |
Each DCS controls a number
of loops. These consist
of a measurement device,
a controller and a valve.
Each loop is composed of
devices to control the flow
of liquid at a particular
point. |
|
Master Modules |
The master is set over the
"slave" module, i.e. is
able to control it. These
are sometimes called "parent"
modules. |
|
MCS |
Management Command
System. A kind of
HMI. |
|
MES |
Management Execution
System. By monitoring
labour resources, process
history and machine usage
& failures, a MES will
help various features such
as preventive maintenance,
employee time & attendance,
quantity maintenance and
operator data. |
|
MIS |
Management Information
System |
|
MMI |
Man-Machine
Interface. Also known
as Human Machine Interface
(HMI). |
|
Migration |
When manufacturers produce
new products they usually
provide a migration path
whereby their existing clients
can upgrade their systems
without total replacement.
Rival manufacturers also
provide migration paths
away from the systems of
others' in order to gain
market share. |
|
MRPII |
Manufacturing Resource
Planning 2.
|
|
Multitasking |
The ability of a computer
to handle more than two
programmes at the same time.
|
|
MTU |
Master Telemetry
Unit |
|
NC |
Numerical Controller
|
|
Neural Network |
A neural network is a computer
network designed to function
in a similar way to natural
neural structures such as
a human brain. |
|
OCS |
Open Control
System. This term
is sometimes used to emphasise
the lack of proprietary
architecture. ABB include
the term in their DCS brandname,
Advant OCS. |
|
OEM |
Original Equipment
Manufacturer. |
|
OFC |
Open Fieldbus
Consortium. |
|
OIS |
Operator Interface
Station. A kind of
HMI. |
|
OLE |
Object Linking
and Embedding, Microsoft's
greatest contribution to
industrial control, allows
operators to link the same
object in several different
applications. |
|
OPC |
OLE for process
control. |
|
Open Systems |
Open systems are customarily
defined as those systems
that can be supplied by
hardware components from
multiple vendors, and whose
software can be operated
from different platforms.
They are opposite to closed
or proprietary systems.
|
|
OS |
An OS is an abbreviation
for an Operating
System which is the
basic computer system which
makes all computers function.
|
|
PC |
Personal Computer
|
|
PFD |
Process Flow
Diagram |
|
PID |
PID stands for proportional,
integral, derivative.
Proportional means changing
a variable in proportion
to its difference from the
set-point. Integral rectifies
any small difference in
the variable and the set-point.
Derivative reduces the other
oscillations. |
|
P & ID |
Process and Instrumentation
Diagram |
|
PIMS |
Process Information
Management System
|
|
PLC |
A Programmable Logic
Controller is a controller
which stores instructions
to command a device, such
as a valve, to which it
is connected to start up,
operate and shut down. |
|
PNET |
The Danish fieldbus. The
Profibus organisation is
seeking to integrate this
in the common Profibus PA
protocol. |
|
Process Variable |
An aspect of the processed
product which changes during
processing, e.g. temperature.
Some variables can be measured,
but in some processes some
variables can only be judged
by dead reckoning. |
|
Profibus |
The German fieldbus, not
to be confused with the
common European fieldbus
Profibus PA. |
|
Profibus PA |
This is the name agreed
on a common European Fieldbus
for process automation,
still disputed by mainly
American companies. Its
main pusher in the industry
is Siemens. |
|
Protocol |
A set of rules to govern
system-to-system use. For
example, a protocol might
specify communication method,
transmission rate, data
format or error check method.
|
|
Redundancy |
This is the capacity to
switch from primary equipment
to standby equipment automatically
without affecting the process
under control. |
|
RIO Bus |
Remote Input/Output
bus. This is a communication
bus used to connect a field
control unit with remote
I/O points or nodes. |
|
RTU |
Remote Terminal
Unit |
|
Safety PLC |
A PLC specifically designed
to be reliable through the
device of redundancy. It
could be used either for
safety reasons or to minimise
the commercial impact of
a serious failure. |
|
SCADA |
Supervisory Control
And Data Acquisition
software. |
|
Set-point |
A desired level for a process
variable. The systems seeks
to correct the variable
when it deviates from this
standard. |
|
SFC |
Sequence Function
Chart. An IEC1131-1
programming/configuration
language. |
|
Single Window |
Single window refers to
the ability to provide multiple
displays via a single terminal.
|
|
Slave Modules |
Slave modules are distributed
modules that report back
to a central master. Despite
the name, they have their
own processing ability.
Another name for them is
"child" modules. |
|
SLC |
Soft Logic
Control. |
|
Smart Device |
A device with intelligence,
i.e. capable of monitoring
itself. |
|
Soft Logic |
A PC operating system used
for soft control. It allows
a PC to replace a PLC. |
|
SPC |
Statistical Process
Control. |
|
Structured Text |
An IEC1131-1 programming/configuration
language. |
|
Tag |
This is a number given to
individual DCS control units
so that the system can identify
them. |
|
TMR |
In safety PLCs, Triple
Modular Redundancy
is the provision of three
micro processors instead
of one in situations where
continuing functioning has
to be ensured. |
|
Trunkwire |
A trunkwire will be possible
for a series of digital
devices. Such a series will
be able to use a single
wire, rather than the multiplicity
of wires used on analogue
devices which all require
separate wiring. |
|
Web Inspection |
In the paper industry cameras
are inserted to monitor
the sheet for visual defects.
|
|
World FIP |
The fieldbus adopted in
France. FIP stands for factory
instrument protocol. The
Profibus organisation is
seeking to integrate this
with the common European
Profibus PA protocol. |
