The I/O Digital Data Point Tag maps
digital tag with two states to an external data source.
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Use caution when using an I/O Digital Data Point Tag to write a bit to a word register with these drivers:
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The I/O Digital Data Point Tag supports the configuration properties of the Digital Data Point Tag plus these properties:
Property | Type | Version | Description |
---|---|---|---|
AllowControls | BOOL | 3.12 | Whether Fernhill SCADA can send controls from this tag to the data source. |
IODataSource | Reference | 3.12 | A reference to another tag that provides the external data for the tag. |
IOItemName | WSTRING | 3.12 | The data item within the external data source. |
InputDelay | TIME | 3.87 |
The minimum time before a change to the input signal is detected.
Use this property to suppress a noisy signal.
Notes:
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OutOfService | BOOL | 3.92 | Whether retrieval of data from the external data source is suspended for this data point tag. |
RawValueInvert | BOOL | 3.12 | Whether the raw value is inverted with respect to the tag state. |
The AllowControls property controls access to the WriteValue Tag Command.
When AllowControls is FALSE, access to the WriteValue Tag Command is blocked. This prevents any user, or program, sending control requests to the data source from this tag. The default value is FALSE to follow security best practice of deny by default.
Even when AllowControls is TRUE, an operator requires the Write User Privilege to send controls to the data source.
For an operator to send a control to the data source, both of these conditions must be true:
The IODataSource and IOItemName properties define which data item the I/O Digital Data Point Tag is associated with:
To configure these properties:
Note: The format of the IOItemName property depends on the type of data source chosen.
To understand how the IOItemName property is formatted, see Data Address Format.
Use the OutOfService property to suspend retrieval of data from the external data source.
For normal operation, OutOfService should be set to False. If a data source is providing faulty data, it might be appropriate to set OutOfService to True.
The RawValueInvert property configures whether the raw I/O value is inverted with respect to the tag value. When enabled, the inversion applies both to data read from the I/O device and also to controls to the I/O device.
The I/O Digital Data Point Tag supports the data properties of the Digital Data Point Tag.
The I/O Digital Data Point Tag supports tag commands of the Digital Data Point Tag plus these tag commands:
Tag Command | Version | Description |
---|---|---|
WriteValue | 3.12 | Writes a new value to the data source via the I/O tag. |
The I/O Digital Data Point Tag builds on the features of these tag types:
To learn about properties common to all digital tags.
To learn about the Core Driver.
For the meaning of terms used in Fernhill SCADA.