stores a variable length string value
internally in the Fernhill SCADA Server.
The Internal String Data Point Tag stores a variable length string value
internally in the Fernhill SCADA Server.
The Internal String Data Point Tag is a license free tag. You can create any number of these tags without restriction.
The Internal String Data Point Tag supports the configuration properties of the String Data Point Tag plus these properties:
| Property | Type | Version | Description |
|---|---|---|---|
| ApplyInitialValue | USINT | 3.13 |
Specifies when the initial value should be applied to the tag. Options are: 0 = Never, 1 = If no value written, 2 = On server restart. |
| InitialValue | WSTRING | 3.13 | The initial value of the tag. |
| ShowWriteValue | BOOL | 3.34 | Whether to show the WriteValue Tag Command in the Standard Tag Menu. |
| ShowWriteValueQuality | BOOL | 3.34 | Whether to show the WriteValueQuality Tag Command in the Standard Tag Menu. |
The ApplyInitialValue property defines when the initial value is applied to the tag. The options are:
| ApplyInitialValue | Description |
|---|---|
| Never |
The initial value is never applied to the tag.
Changes to the InitialValue field have no effect. New tags will be initialized with an empty string and bad quality. New tags include those created by copying existing tags. If the Fernhill SCADA Server is restarted, the value of the tag is preserved. |
| If no value written |
If no value has been written to the tag, the InitialValue field is applied to the tag. Changes to the InitialValue field will be applied to the tag until the first value is written. After the first value is written, changes to the InitialValue field have no effect. New tags created by copying an existing tag will be initialized with the InitialValue and good quality. If the Fernhill SCADA Server is restarted, the value of the tag is preserved. |
| On server start |
If the Fernhill SCADA Server is restarted, the initial value will be written to the tag. Changes to the InitialValue field will be applied to the tag until the first value is written. After the first value is written, changes to the InitialValue field have no effect. New tags created by copying an existing tag will be initialized with the InitialValue and good quality. |
Note: Values are written to the tag using one or both of these tag commands:
The Internal String Data Point Tag supports the dynamic properties of the String Data Point Tag.
The Internal String Data Point Tag supports tag commands of the String Data Point Tag plus these tag commands:
| Tag Command | Version | Description |
|---|---|---|
| WriteValue | 1.2 | Writes a new value to the tag. |
| WriteValueQuality | 1.2 | Writes a new value and quality to the tag. |
The Internal String Data Point Tag builds on the features of these tag types:
To learn about properties common to all String Tags.
To learn about the Core Data Driver.
For the meaning of terms used in Fernhill SCADA.