is an abbreviation for Supervisory Control and Data Acquisition
and as such has emphasis on the supervisory level of the system.
It is a software application that is positioned above the
hardware of the system architecture and interfaces to it via
a central control host and a number of Programmable Logic
Controllers (PLC's) or other commercially available hardware
modules. SCADA systems are ideally suited for the remote control
of industrial and experimental processes and are available
in configurations of hundreds of input/output (I/O) channels
to hundreds of thousands of channels in some applications.
SCADA is a rapidly developing technology that is penetrating
many areas of remote and distributed control.
industrial measurement and control system would consist of
a central host or Master Terminal Unit (MTU), a number of
Remote Terminal Units (RTU's) used to collect field data plus
application software for the monitoring and control of all
remote data sub-systems.
is predominately used in longer distance communications applications
and utilises a variety of communications medium mostly in
an open-loop control structure. Alternatively, the control
structure may be a combination of open-loop and closed-loop
control combined with elements of short distance control.
Control Systems (DCS) are also commonly encountered in production
plants and smaller industrial processes including research
and development areas. These are mostly closed-loop control
systems that operate over a confined area and offer high speed
communications over Local Area Networks (LAN) with high integrity.
control may be automatic or manually controlled by operator
commands. Data monitoring is achieved by the RTU's (PLC or
process controller) scanning the field inputs at a fast rate.
A specific RTU requires a sufficient real-time bandwidth for
the monitored processes and has distributed intelligence to
deal with the monitoring task. The MTU then scans the system
at a slower rate looking for alarm conditions and reporting
data is usually a combination of 3 types. Analog outputs may
be acquired at fixed intervals with the results either trended
graphically or updated as numeric values in engineering units.
Digital data (On/Off) represents the state of switches or
valves or even alarm conditions. Pulse data is used to count
revolutions and determine the speed of rotating machinery.
Machine Interface (MMI) is usually a graphical mimic display
representation of the plant or selected area of the plant.
The live data from the field inputs is superimposed on this
static background and the foreground changes according to
changes in the process. Operator awareness is heightened by
the use of colour, animation and sound. The MCU will generate
histograms (trending), control data logging and handle alarm
conditions. Additional tasks may involve report generation,
the archiving of data and data automation triggered by events.
is offered in the design, configuration and implementation
of SCADA based plant control systems. Customers can expect
significant cost saving in the development and maintenance
of a complex control process using this system. These potential
benefits arise from the understanding of current industrial
standards at both the client layer and the data server layer
in addition to a system design approach that includes functionality,
scalability, performance and openness.
design is implemented within an established framework with
an emphasis on reliability and robustness to produce systems
to the highest standards of performance for critical industrial
processes. High quality engineering is paramount to achieving
all of the above performance requirements and requires an
organisation with experience that is familiar with new technologies
and emerging trends in the area. The full range of services
includes customer or end user training and after sales technical
support and service.
view our Control
page for further information.