Geo SCADA Expert is able to read and/or write to data on other servers using one of two OPC standards: OPC DA, and OPC XML-DA. Whether you choose to use the Geo SCADA Expert Advanced OPC Driver, the Geo SCADA Expert Guide to the Simple OPC Driver, or the Geo SCADA Expert OPC XML-DA Driver, depends to some extent on your system setup.
OPC DA is more efficient in terms of network bandwidth than OPC XML-DA. However, OPC DA is based on DCOM and can be problematic to set up when the driver and target OPC DA server are on opposite sides of a firewall. OPC XML-DA uses standard web protocol and is much more firewall friendly. If network bandwidth is important, use the Geo SCADA Expert Advanced OPC Driver, or the Geo SCADA Expert Simple OPC Driver, to communicate using OPC DA; if easy setup is important, use the Geo SCADA ExpertOPC XML-DA Driver to communicate using OPC XML-DA.
The Geo SCADA Expert Advanced OPC driver provides additional functionality to the Geo SCADA Expert Simple OPC driver, such as support for redundant OPC servers. If both the Advanced and Simple OPC drivers provide the required functionality, consider using the Advanced OPC driver rather than the Simple OPC driver. Using the Advanced OPC driver will give you more flexibility should your system requirements change in the future.
For information on the other OPC drivers, see the Geo SCADA Expert Guide to the Simple OPC Driver, and the Geo SCADA Expert Guide to the OPC XML-DA Client Driver respectively