ROC Plus Driver Guide - Control Tab (Database Objects)

Control Tab

Display the properties window (‘configuration Form’) for a ROC Plus Numeric Point object and then select the Control tab.

The tab displays the standard Control properties for a Geo SCADA Expert analog point (see Define the Analog Control Settings in the Geo SCADA Expert Guide to Core Point Configuration).

If the Enabled check box is selected, you will get access to the control aggregate and 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 value.

NOTICE

UNEXPECTED BEHAVIOR OF APPLICATION

Ensure that the Maximum and Minimum values on the Control tab are set correctly for the TLP with which the point is associated

Failure to follow these instructions can result in equipment damage.

When the Control method on the Control aggregate is called from the object menu, or from a pick action without a parameter specified, Geo SCADA Expert will prompt the user for a new value that is within the range of the Minimum and Maximum settings. It is important to set the Minimum and Maximum values on the Control tab correctly for the TLP that is referred to by the point. For example, a TLP that refers to a UINT8 value can only hold 8 bits, and has a range of 0 to 255. A control request to 324, for example, could have unintended consequences.

ATTENTION: If a user specifies a decimal value for a TLP that refer to an unsigned integer, the driver will truncate the value and write it to the ROC. For example, a write request of 13.6 for a TLP that refers to a value that is of type UINT8 will result in the value of 13 being written to the ROC. This is because unsigned integers cannot hold values with fractional components.

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.