NOTE: You only need to create and configure an Advanced Modbus Remote Connection if ClearSCADA is to share a communications link with other software applications (such as ISaGRAF) in order to communicate with Modbus controllers. An Advanced Modbus Remote Connection is not required if ClearSCADA and the other software applications use separate communications links to interrogate Modbus controllers.
An Advanced Modbus Remote Connection allows ClearSCADA to share a link with software applications such as ISaGRAF, such that both ClearSCADA and the other application(s) use the same link to communicate with Modbus controllers. With a shared connection, ClearSCADA acts as a ‘gateway’, to allow such applications to interrogate the controllers remotely. When the applications communicate with Modbus controllers via ClearSCADA, the application software communicates with ClearSCADA, and then ClearSCADA communicates with the controllers.
For systems on which such applications are to use ClearSCADA to communicate with Modbus controllers remotely, you need to configure one or more Advanced Modbus Remote Connections. Each Remote Connection provides a TCP/IP socket connection between ClearSCADA and the remote applications (such as ISaGRAF). ClearSCADA extracts the address information from any messages sent via this connection, in order to establish the Modbus controller to which the messages relate. ClearSCADA then interrogates the appropriate controller and sends the data on to the remote application.
You need to configure one Advanced Modbus Remote Connection in the ClearSCADA database per TCP/IP port that a remote application is to use to communicate with ClearSCADA. One Remote Connection can enable multiple applications to communicate remotely with numerous Modbus controllers.
You configure the properties for each remote connection using the fields on the Advanced Modbus Remote Connection Form.
The Form has several tabs.
Use the Remote Connection tab to:
- Specify Whether a Remote Connection is Active (see Placing an Item In Service in the ClearSCADA Guide to Core Configuration)
- Specify whether a confirmation dialog box is displayed whenever an operator requests that the Remote Connection is disabled or enabled (see Requesting Confirmation of Action Requests in the ClearSCADA Guide to Core Configuration)
NOTE: Users with the required permissions can disable the Remote Connection if it is In Service, or enable it if it is not In Service. Such actions are performed using the Disable Channel and Enable Channel pick actions. If a Remote Connection is disabled, the external application that uses it will not be able to communicate with the remote controllers. This will not affect any other database items in ClearSCADA.
- Define the Severity of any Alarms or Events (see Defining Severities in the ClearSCADA Guide to Core Configuration)
- Specify Whether On Demand Outstations Support Open Connections for Remote Messages
- Specify the Frequency with which Communications Statistics are Updated
NOTE: If the Area of Interest feature is enabled on your system, an additional Area of Interest field is displayed immediately below the Severity field. Use the field to specify the Area of Interest with which any remote connection alarms or events are associated (see Assign a Different Area of Interest to an Item’s Alarms and Events in the ClearSCADA Guide to Core Configuration).
For more information on the Area of Interest feature, see Restrict Alarm and Event Access to Specific Areas of Interest in the ClearSCADA Guide to Core Configuration.
Use the Connection tab to:
For information on the fields on other tabs, see Tabs that are Common to Many Configuration Forms in the ClearSCADA Guide to Advanced Drivers.
NOTE: To display remote connection details in List format from the Queries Bar, filter the constraints on the Channels List.