Most drivers enable ClearSCADA to be the SCADA Master. When the ClearSCADA server is the master, ClearSCADA initiates and controls the transmissions to and from the other devices on the system. (The exception to this being any outstation that has the ability to send unsolicited messages to ClearSCADA, to inform the server of any new alarms that have been generated at that outstation.) When ClearSCADA is the master, any sensors or control devices are represented by points in the ClearSCADA database. The driver-specific documentation specifies which type(s) of point are supported by each driver and explains how to configure those points. For general information on points, see the ClearSCADA Guide to Core Point Configuration.
Some drivers enable ClearSCADA to be a Slave. When ClearSCADA is a slave, the server acts like an outstation and reports any changes to another SCADA master. The SCADA master may be another ClearSCADA server, or a third-party server. When ClearSCADA is a slave, any ‘point’ data is mapped into a simple block of memory in the driver, using a Value Map or Filtered Value Map (see Configuring Value Maps in the ClearSCADA Guide to Core Configuration). The driver-specific documentation specifies which type(s) of Value Map and/or Filtered Value Map a particular slave driver supports.
If a ClearSCADA driver is a slave driver, the word ‘Slave’ is included in the driver name. Drivers that do not include the word ‘Slave’ in their name typically enable ClearSCADA to be the SCADA Master.
With any ClearSCADA driver, refer to the driver-specific documentation for information on which database items you need to configure in ClearSCADA, in order for ClearSCADA to be either the SCADA Master or a Slave.
Be aware that it is possible for ClearSCADA to be both a SCADA Master and a Slave, if both master and slave ClearSCADA drivers are installed on a system.
The diagrams in the remainder of this section demonstrate each of the above setups:
- ClearSCADA Configured as a SCADA Master
- ClearSCADA Configured as a SCADA Slave
- ClearSCADA Configured as both a SCADA Master and a SCADA Slave.
Be aware that these diagrams are very simplified versions of each system—a ClearSCADA system typically comprises one or more servers (of which one will be ‘Main’) and multiple ViewX and/or WebX clients (user workstations). For more information, see Understanding Your System in the ClearSCADA Guide to ViewX and WebX clients. For more information on server setups, see System Architectures in the ClearSCADA Guide to Server Administration.
Further Information