OneSix Server Help
Overview
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Filtering
For both analog and temperature devices, OneSix
™
allows the user to define a
deadband to control the amount of change that must occur before the server updates a
Client with new data. Deadband is useful to control the amount of information that is
passed through OPC to the client application. For analog devices, the deadband is
entered as the percentage of full scale of Engineering units. For temperature devices,
the deadband is entered in degrees C.
Also for both analog and temperature devices, One Six™ provides the means to filter
the data with either an Average, Median or combination Median Average filter
before either logging data or delivering data through OPC. In the One Six INI file,
you specify the filter type and the number of samples to filter.
What is OPC?
OLE for Process Control (OPC) is a specific specification of Microsoft’s Object
Linking and Embeddeding (OLE) and Component Object Model (COM) that is
administered by the OPC Foundation (150 member companies including Microsoft
Corporation). OPC provides a common interface for devices and applications to
communicate. Devices that gather or originate data become OPC servers, providing
data to OPC client applications in a consistent fashion. At the heart of OPC is the
client/server model in which the OPC server provides and interface to the OPC
object, allowing client applications to control devices and manage device data in a
generic fashion. OPC servers can be accessed through most HMI software and
through a variety of languages, including C++, Visual Basic, and Delphi. The OPC
server collects data from physical devices for distribution to OPC client applications
and also has the responsibility for updating device data when an OPC client issues a
write.
An OPC client connects to and communicates with an OPC server through one of two
interfaces defined in the OPC specification. The OLE automation interface allows
users to access data through the use of a common, easily understood scripting
language. The COM interface is more complex, but provides finer levels of control
and flexibility for developers and users proficient in languages such as C or C++.
OPC client applications can access OPC servers locally within a computer or from a
networked server.
Data Logging
OneSix™ Server can log data to an ASCII file at a programmable interval. The
default name of the file is ONESIX.LOG.
A client application can control logging through OPC variables. The client can
start/stop logging or just log a single record.
For diagnostic purposes, OneSix™ can log errors that have occurred while waiting
or process device data.
For more information see the section OneSix Server Data Logging.
