CIRCUTOR OPC Server PS/PSS - Manual (Page 4)

PS/PSS OPC Server -4-
2.- OPC (OLE for Process Control)
OPC is a communications standard in the world of process control and process data
monitoring that allows different data sources to send information to a single server or data
acquisition system which, in turn, can be accessed by different programs that are
compatible with the mentioned standard. In this way, there is no need for each and every
program to have specific drivers to communicate with multiple data sources. They just
need an OPC driver.
To make this communication work, the OPC standard defines a set of protocols,
where each of them has its own particular purpose. The OPC server for PowerStudio and
PowerStudio Scada implements the DA (Data Access) protocol, which is responsible for
the exchange of data in real time between servers and clients.
3.- PowerStudio / PowerStudio Scada OPC Server
In our case, the data source will be PowerStudio SCADA and the OPC server will
make it possible for any OPC-DA client or software which implements it, to access the
values of the variables of the various devices made available in the desired PowerStudio
server.
In order to be able to use the PowerStudio OPC server you must have the HASP
key, or dongle, with the corresponding active licence connected to the PC's USB port. If
this dongle is not available, the server will run in demonstration mode, with the following
limitations:
• 15 minutes of use (after this time the variables will no longer be updated, with
no more requests being made to PowerStudio).
3.1.- General description of the server
The server is based on a Windows service and adds the possibility to communicate
with the PowerStudio engine via OPC. On the one hand, it handles the variable value
requests from the OPC client and, on the other, it makes the corresponding XML requests
to PowerStudio in order to get the values of the variables that have been requested.
PowerStudio OPC is compatible with versions 1.0, 2.0 and 3.0 of the OPC-DA (Data
Access) specification. It also supports various operating modes which allow its use to be
optimised according to your needs and it is fully configurable through its user interface.
3.2.- Setup utility
This is the utility that allows you to configure and manage the PowerStudio OPC
server, setting up all of its operating parameters. This tool also allows you to maintain
various different configuration profiles, offering increased flexibility and adaptability by
giving you the chance to change the behaviour of the server almost in real time. There are
three main aspects that determine the behaviour of the server for each of the created
configurations:
• PowerStudio (data source) connection data
• OPC server configuration
• List of active devices