On a ClearSCADA system, you configure the ClearSCADA database so that entries in the database correspond to the plant, control devices, and measuring instruments on your system. This section summarizes the database items that you need to configure in order to read and write data to Allen-Bradley PLCs using the DF1 protocol.
To communicate with Allen-Bradley PLCs using DF1, the DF1 Driver has to be installed and running on the ClearSCADA servers on your system. The driver is represented by the Allen-Bradley DF1 component in the ClearSCADA Installation Wizard’s Setup window. The component is located within the Server branch of the tree that is displayed in the window (see Install a Driver in ClearSCADA in the ClearSCADA Guide to Drivers.)
When you configure DF1 items in the ClearSCADA database, many of the settings for those items need to correspond to the settings on the Allen-Bradley PLCs on your system. Some settings are either fixed (incorporated into the design of the Allen-Bradley PLC), or are configured by an engineer. You need to have access to, or an understanding of, these settings before you can configure the DF1 database items successfully.
For instance, you need to know the type(s) of Allen-Bradley PLC that the DF1 driver is to scan, and the identification numbers of the files in which the point data resides.
You also need to be aware of which optional features are required for each DF1 item. These features include:
- Alarm views
- Alarm redirections
- Historic data storage
- User methods.
You can also use core ClearSCADA features with DF1 database items, including Lists, Actions, and Mimics. See the core documentation for details.
For each DF1 device, you need to configure:
- DF1 Channel(s) to represent the communication connections between each Allen-Bradley PLC and the ClearSCADA server (see Configuring a DF1 Channel).
You need to configure a separate DF1 channel for each separate communications channel that is available to the DF1 driver on your system.
- At least one DF1 Scanner for each Allen-Bradley PLC that the DF1 driver is to scan (see Configuring a DF1 Scanner).
Configure a scanner for each group of points that you want to scan at a different frequency, or that have a different data type.
- A DF1 Point for each separate item of data that is to be read from or written to in an Allen-Bradley PLC (see Points Used on DF1 Scanners).
You can associate multiple points with each DF1 Scanner.
To minimize the time that it takes to configure the DF1 items, you may want to configure them in the order listed above, as Scanner configuration requires that you specify a Channel, and Point configuration requires that you specify a Scanner, and so on.