This feature allows a pair of LinkMaster machines to operate
in redundant pairs where one LinkMaster machine operates as the
"Primary" node and the other as the "Secondary" node. When the
"Primary" node fails, the "Secondary" node promotes itself and
takes over the role of the primary. When the "Primary" node comes
back up again, the "Secondary" node demotes itself and the "Primary"
node performs the data transfer once again.
Supports COM and DCOM
Based on Microsoft's COM technology, OPC servers can share
data with remote client applications using DCOM (Distributed
COM). DCOM allows you to use a single OPC server to provide
data to client applications running both locally and on remote
machines. DDE is not without its own means of allowing remote
access. All of the DDE formats supported by LinkMaster can
also be accessed remotely using what is known as NETDDE. NETDDE
allows a remote DDE client application to use the machine name
of a remote DDE server when specifying a DDE link. LinkMaster
has been designed to allow both of these methods of remote
server access. In terms of OPC connections, LinkMaster will
properly configure your DCOM settings to allow remote OPC clients
to access and browse LinkMaster. For DDE clients, LinkMaster
will automatically start NETDDE services and register all of
the required DDE shares, allowing remote DDE clients access
to device data. Establishing DDE share names can be a time
consuming process for the application, therefore, by default,
NETDDE services are not enabled in LinkMaster.
Runs as a Windows Service
LinkMaster supports running as a Windows service.
Service operation is completely user configurable from the
Tools|Options menu, and can be changed at any time allowing
you to move from normal, stand alone program operation, to
NT service mode. Running as a NT service is crucial for many
applications where LinkMaster is providing data to OPC clients
via DCOM. For these applications, loss of a DCOM connection
can not be tolerated. Normally, an OPC server that only supports
stand alone program operation is forced to shut down when the
host machine experiences a user log in or log out. While running
as a service, LinkMaster can continue to supply OPC data across
user log in sessions and can be configured to interact with
the desktop, allowing you to make changes to your LinkMaster
project. It can also be configured to have a non-visible presence
LinkMaster supports direct scaling of link item data. Scaling
allows raw data to be converted to engineering units for OPC
client applications. LinkMaster provides a number of unique
scaling features, such as Linear and Square Root formula scaling.
You can also specify the range of the raw data input and the
engineering range of the scaled value. In some cases, the raw
data input received may exceed the range set for the raw data.
If this occurs, the engineering value can be forced outside
of the range you desire. To prevent this, LinkMaster allows
you to clamp the scaled value to the engineering ranges. In
most cases, it is always assumed that a scaled value results
in a floating point number. LinkMaster doesn't make this assumption
and allows you to select the scaled engineering value to be
any valid OPC data type. This means you can scale a 16-bit
integer value to a 32-bit integer value.
Link Item Management
LinkMaster's link management system allows you to create
a Link database structure that fits the nature of your
Multiple Link groups can be added and defined to segregate
your Link items into meaningful groups. Drag and drop editing
makes adding a large number of tags easy. Unique Link Management
features allow new links to be created on the fly using
and Drop" and "Tag Browsing" methods.
In certain situations, managing what your users can and cannot
do in your OPC application can be a necessity. LinkMaster includes
a built in User Manager that allows complete control over what
types of functionality each individual user can access. The
default administrator account allows you to add multiple users,
each with their own set of rights for LinkMaster access. Any
user log in/log out is recorded in LinkMaster's event logging
system- the EventViewer. By default, all operations are available
at all times until you decide to set privileges.
Included with the LinkMaster package is a stand alone event
monitoring application called the EventViewer. The EventViewer
is a 32-bit Windows application that monitors and displays
events occurring on any running LinkMaster application, either
remotely or locally, allowing multiple LinkMaster systems to
be monitored concurrently.