Points on a remote outstation can be scanned:
- By a data concentrator (the remote outstation’s ‘parent’ outstation)
- Directly by ClearSCADA, with communications being transmitted ‘transparently’ through the parent outstation
- Both of the above.
If a data concentrator is to scan its remote outstations for data, you need to specify the type of polling regime that the data concentrator is to undertake, and the internal Derived (User) points that are used to control and monitor such polling. Use the fields on the Remote DNP3 Device tab of the DNP3 SCADAPack Remote E Outstation or DNP3 SCADAPack Remote DNP3 Device Form to Specify the Remote DNP3 Device Properties.
The frequency with which ClearSCADA polls the data concentrator for data, and the ability of the data concentrator to transmit unsolicited messages to ClearSCADA, determines the frequency with which the data concentrator’s copy of the remote outstations’ data is transmitted to ClearSCADA. (Should communications be temporarily lost between ClearSCADA and a data concentrator, the data concentrator will continue to poll its remote outstations for data.)
If ClearSCADA is to scan remote outstations for data, you specify the required scanning regime for the remote outstation’s points in the same way as you would for points on any ‘local’ SCADAPack E or generic DNP3 outstation. ClearSCADA scans the outstations for data as if they were ‘local’ outstations, other then that transmissions go ‘transparently’ through the remote outstations’ parent outstation. As such, communications with the parent outstation have to be healthy, in addition to the remote outstations.