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Overview
WebLink is the internet - aware NTMC component. It
serves as an internet interface, and an e-mail engine.
As an internet interface WebLink performs several functions.
- It enables NTMC operators to decide which NTMC
objects (such as load points,
meters, etc) are visible via
the internet. With the help of MCSA, the operators can also specify who
has access to those objects via the internet.
- It enables all persons who have a security account on NTMC
to view NTMC objects using a standard web browser.
- It enables all persons who have a security account on NTMC
to issue commands to NTMC (such as read a meter,
operate a load, etc) using a standard web browser.
- It allows any software with appropriate security credentials to
communicate with NTMC via the internet.
As an e-mail engine WebLink allows operators to specify which NTMC
objects generate e-mail, and events that trigger e-mail generation. Operators
can also specify which users are recipients of those e-mail messages.
NTMC Object Definition
Operators first define NTMC objects that are to be
involved in internet-related activities. At that stage objects are defined in
WebLink database, and nothing more. An example of an object might be
\Component:RUEX\Domain:Substations\RemoteUnit:Sub09\AnalogPoint:Demand\Demand:Value.
This translates (reading above from right to left) into the following:
- The object is an analog
point called Demand;
- It is associated with remote
unit called Sub09;
- This remote unit is in domain
called Substations;
- This domain is in a database managed by RUEX.
Furthermore, the keyword Value at the end of the object definition
specifies that we want to display the analog point's value, as opposed to one
of its configuration parameters.
Please click here to see how to
implement this.
NTMC Object Publishing
To be published (visible) on the internet, each object must be marked
appropriately. Objects marked for publication are picked up by other NTMC
components and updated with latest values. These objects' data are then
replicated to the internet server, where they are ready to be viewed by any
person who has a security account on NTMC .
Please click here to see how to
implement this.
NTMC Object Viewing
Viewing of published NTMC objects is done by using a
standard web browser. A viewer first logs on to NTMC, and
then navigates to the part of the system of interest. Server - resident
components of WebLink process viewer's requests by accessing the server -
resident object and security databases. Object data is then downloaded to
viewer's browser as long as the viewer has sufficient security credentials to
see the object.
Please click here to see how to
implement this.
Issuing Commands to NTMC via the Internet
Viewers can issue commands (poll a remote
unit, operate a load point,
etc) to NTMC with a click of a mouse. Commands are only
available to viewers with sufficient credentials. Commands are first qued on
the server. They are subsequently downloaded to NTMC in
the control room, where they are processed within seconds.
Please click here to see how to
implement this.
Interfacing with NTMC via the Internet
Other software anywhere on the internet can execute NTMC
functions exposed to
the internet as long as that software has security credentials, and is able to
consume Microsoft .Net web services. This makes it possible to have NTMC
communicate with other SCADA systems, other NTMC systems,
or any systems out there capable and interested in such communications.
Please click here to see how to
implement this.
E-Mail
Operators can specify which NTMC
objects generate e-mail, and events that trigger e-mail generation. These
events can be alarms (objects generate e-mail on every new alarm), or changes
in object value (a load point generates
an e-mail message every time it goes from ON to OFF, and vice versa, for
example).
Operators
can also specify which users are recipients of those e-mail messages. Each
e-mail generating object can notify as many people as desired. In addition,
every e-mail recipient can have as many e-mail addresses assigned as desired.
Note that nowadays e-mail can not only be sent to computers, but also to
cell phones, pagers, PDAs, etc.
Please click here to see how to
implement this.
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