Display the properties window (‘configuration Form’) for a ROC Plus String Point object and then select the Control tab.
The tab displays the standard Control properties for a ClearSCADA string point (see Define the Control Settings for a String Point in the ClearSCADA Guide to Core Point Configuration).
If the Enabled check box is selected, you will get access to the control aggregate and you can call the Control method on the point to change a parameter’s value in the ROC, as long as the TLP for the point refers to a writable string value.
When the Control method is called from the object menu, or from a pick action without a parameter specified, ClearSCADA will prompt the user for a new string value. The string entered by the user is either padded with spaces or truncated so that the number of bytes matches the value in the TlpValueSize tag. ROC devices do not support Unicode. The string has to be in ASCII format.
After calling the Control method, we recommend that you check the Event Journal (‘Events List’) to ascertain whether the control was successful. Following a successful control request, the driver will write the new value to the ROC and then read the value back from the ROC. It will then update the point’s value to the new value in the database. On an unsuccessful control request, the point’s value will not change. In addition to the Event Journal, you can look at the LastError tag on the point object for the response of the ROC to a failed control request.