Q: How is LIO
different than OPC client toolkits?
A: There
are two main differences beyond it being a native .NET assembly. The most
important difference is that the other commercial toolkits basically provide a
thin interface into the OPC server. You start building your
application from these basic APIs. LIO on the other hand is a tag
server component (dll) that links to your application and provides you
native .NET style classes, events, properties, etc. The OPC server
keeps the LIO tag server up-to-date in the background without you doing any
work. Your application simply access the IOTags when ever it wants or
uses Updated and PropertyChanged events to monitor changes or even
communications failures to the OPC server. See the operational
overview for more on this
topic.
Q: Does LIO
support DCOM for OPC?
A: Yes.
One might think that the term "Local" in LIO implies no networking support.
However, this really refers to the application's client interface and not
the supported protocols. When we add Modbus TCP it will still be
"Local" IO. Once we move the TagServer to a Windows service and allow
connections via .NET remoting, then we have a product called Remote IO.
(So this is a front-end term not a backend term.) You can even use the
TagServer class to get a list of network hosts and check for OPC servers of
ANY type on any node via OPCEnum.
Q: Isn't LIO just an OPC client
DLL?
A: Not really. LIO is
intended to encapsulate any possible industrial protocol with a generic
real-time data access interface. OPC was chosen to be the first
interface implementation due to its wide acceptance and the variety of
protocols supported by existing OPC servers. LIO eliminates the need
for protocols and replaces it with a simple generic real-time-data
object interface. In fact, event though some native OPC information is
available, you cannot access any of the OPC specific COM
functions through LIO.
Q: Can you
use LIO in a Windows service?
A: Yes.
We have customers doing this now. There are no UI MessageBoxes etc.
that pop up while running unless you are already using the built-in UI.
All error messages can be received by your application via the TagServer's
Errored event or they can be routed to the Windows Event Log for you by the
TagServer class.
Q: How is LIO Licensed?
A: LIO is licensed on a per
developer seat basis. There is no runtime license for the developer's
resulting application. You can also obtain a developer's 3 pack license
for a reduced rate and a source code license. If you need to move your license to
another computer, just email us and we will issue you another license key.
