Calculated Long Word Data Point Tag

Help Contents

Introduction

The Calculated Long Word Data Point Tag Long Word Data Point Tag Icon maps a 64-bit unsigned integer to the result of a calculation. The calculation can run:

Configuration Properties

The Calculated Long Word Data Point Tag supports the configuration properties of the Long Word Data Point Tag plus these 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 timed activities are scheduled.
UpdateOffset TIME 1.3 The offset added to the UpdateInterval to get the actual update time. See Interval and Offset for information on how timed activities are scheduled.
InstructionLimit UDINT 1.3 The maximum number of instructions to execute.

Calculation

The value of the Calculated Long Word tag is the result of an IEC 61131-3 Expression.

The expression should return a value of type ULINT.

The expression is evaluated:

Setting UpdateInterval to T#0s disables periodic evaluation.

To edit the calculation:

  1. Right-click the tag in the Tag Window.
  2. Select Edit Calculation.

The calculation is edited using a Program Code Editor.

Data Properties

The Calculated Long Word Data Point Tag supports the data properties of the Long Word Data Point Tag plus these properties.

PropertyTypeDescription
ExecErrorCode DINT The result of the execution. A zero value shows success. A non-zero value shows 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 STRING[120] The execution error message. An empty string shows no error.
UpdateTimer TimerStatus The status of the calculation update timer.

Tag Commands

The Calculated Long Word Data Point Tag supports tag commands of the Long Word Data Point Tag plus these tag commands:

Tag Command Version Description
Run 1.3 Evaluates the expression and writes the resulting value to the tag.

Relationships to Other Tag Types

The Calculated Long Word Data Point Tag builds on the features of these tag types:

Further Information

Interval and Offset

To learn how activities are scheduled using Interval and Offset.

Expressions

To learn about the expressions that can used in the Calculation property.

Long Word Data Point Tag

To learn about properties common to all Long Word Tags.

Core Data Driver

To learn about the Core Driver.

Glossary

For the meaning of terms used in Fernhill SCADA.