The SCADAPack Modbus Driver enables ClearSCADA to communicate with Schneider Electric’s range of SCADAPack RTUs, using the Modbus protocol. The driver supports standard Modbus communications options, but also includes additional functionality that is required to support specific features in the SCADAPack RTUs. For example, DLOG time-stamped historic data, which the SCADAPack Modbus driver can retrieve from each SCADAPack RTU and store in the ClearSCADA database.
The SCADAPack Modbus driver also provides additional functionality for ‘generic’ Modbus devices, as well as SCADAPack devices, including PSTN support (whereby Modbus devices can be dialled from ClearSCADA and vice versa). The SCADAPack Modbus Driver can communicate with Modbus devices using any of the following communication mechanisms (the ClearSCADA Simple Modbus Driver also supports those marked *):
- Modbus ASCII over a serial, TCP or UDP connection
- Modbus RTU over a serial*, TCP* or UDP connection
- Modbus TCP over a TCP*, or UDP connection.
With the SCADAPack Modbus driver, you assign each point an Address and a Retrieval Interval. The Retrieval Interval determines the frequency with which ClearSCADA polls a Modbus device for point data. Reads are blocked together for Retrieval Intervals that coincide for points within the same register range (for example, Input Registers), to determine the most efficient polls automatically.
If your system is to communicate with SCADAPack RTUs, or requires any of the additional functionality listed above, use the ClearSCADA SCADAPack Modbus Driver to communicate with the Modbus devices on your system—for further information on configuring items on the SCADAPack Modbus driver, see the ClearSCADA Guide to the SCADAPack Modbus Driver. If, however, the ClearSCADA Simple Modbus Driver fulfills your system requirements, either driver can be used.