maps a 32-bit unsigned integer to the result of a calculation.
The calculation can be periodic, or requested on demand or a combination of the two.The Calculated Double Word Data Tag maps a 32-bit unsigned integer to the result of a calculation.
The calculation can be periodic, or requested on demand or a combination of the two.
The Calculated Double Word Data Tag supports the configuration properties of the Double Word Data Tag plus these additional configuration properties:
| Property | Type | Version | Description |
|---|---|---|---|
| UpdateInterval | TIME | 1.3 | The interval between each calculation. A value of zero (T#0s) disables periodic calculation. See Interval and Offset for information on how Intervals and Offsets define the time of activities. |
| UpdateOffset | TIME | 1.3 | The offset added to the UpdateInterval to get the actual update time See Interval and Offset for information on how Intervals and Offsets define the time of activities. |
| InstructionLimit | UDINT | 1.3 | The maximum number of instructions to execute. |
The Calculated Double Word Data Tag evaluates a Calculation at the periodic interval defined by the UpdateInterval and UpdateOffset properties. The result of the calculation is written to the tag. Setting UpdateInterval to T#0s disables periodic calculation.
The value of the Calculated Double Word tag is defined using an IEC 61131-3 Expression.
To edit the calculation, right-click the tag in the Tag Window, and then click Edit Calculation. The calculation is edited using a Program Code Editor.
The Calculated Double Word Data Tag supports the dynamic properties of the Double Word Data Tag plus these properties.
| Property | Type | Description |
|---|---|---|
| ExecErrorCode | DINT | The result of the execution. A value of zero indicates success. A non-zero value indicates an error occurred. |
| ExecErrorLocation | DWORD | The address of the instruction that caused the error. Zero if there was no error. |
| ExecInstructionCount | UDINT | The number of instructions processed by the program during the latest execution. |
| ErrorMessage | WSTRING | The execution error message. Empty string indicates no error. |
| UpdateTimer | TimerStatus | The status of the calculation update timer. |
The Calculated Double Word Data Tag supports tag commands of the Double Word Data Tag plus these tag commands:
| Tag Command | Version | Description |
|---|---|---|
| Run | 1.3 | Evaluates the expression and writes the resulting value to the tag. |
The Calculated Double Word Data Tag builds on the features of these tag types:
To learn how activities are scheduled using Interval and Offset.
To learn about the expressions that can used in the Calculation property.
To learn about properties common to all Double Word Tags.
To learn about the Core Driver.
For definitions of the terms used in Fernhill SCADA.