Digital Output Tags
Digital output tags take digital information from the user or from another tag and write it to the I/O device. Digital output tags provide drawing methods to change the state of the output via button controls.
The value of a digital output can be:
• 1 when there is an attempt to set the output that has not yet been confirmed by a change in the feedback value;
• 0 if neither case is met. i.e. when not performing a write, or after confirmation is received that a write has occurred.
• Of interest to programmers: A transient value of 2 will occur when the feedback value changes without any prompting from the digital output. This value is extremely transitory and will not be caught by an alarm.
The characteristics of the digital output are identified in the table below.
Digital Output Characteristics
Tag Browser Name: Digital Output
Database Table Name: DigitalOutput
Type: Input/Output Tag
Tag Group Memberships: Digitals, Numeric, Outputs, Trenders
Log Enabled Variables: Value
Native Drawing Methods: Digital Output Tag Drawing Methods
Note: Remember, the existence of an output tag is not enough to output a value to the I/O device; you must draw the tag using a control drawing method (such as a Set Value Button) to enable users to send a value to the I/O device and related equipment.
Digital Output Tag Type Properties: ID
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Digital Output Tag Type Properties: I/O
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Digital Output Tag Type Properties: Feedback
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Digital Output Tag Type Properties: Owner
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Digital Output Tag Type Properties: Merit
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Digital Output Tag Type Properties: Alarm
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