DO/DI Proof

Source graphics  The information below provides a FULL description of this microblock and all of its properties. What information you see and what you can do with it depends on your license and the application you are in.
 

Microblock family

Misc microblocks

Icon and symbol

  

What it does

A DO/DI Proof microblock verifies proper equipment operation by comparing the status of a digital input with the status of a corresponding digital output.

For example, the microblock can compare an input indicating the fan's on or off status with the output that turns the fan on or off. If the two inputs do not receive the same signal, the DO/DI Proof microblock provides two outputs that can be used to trigger alarms.

Source graphics

Properties

Source graphics TIPS

  • Alt+click any value in the i-Vu® or Field Assistant interface to view property details, including its editing privilege and expression (location path) for use on graphics.
  • You can right-click some properties in the Snap Property Editor and select Make editable or Make read-only to determine that property's functionality in your system.

Reference Name
RefName

Use the default reference name unless you want a more descriptive name for graphics or network links.

Limitations:

  • lower case only
  • limited to 40 characters
  • cannot begin with a number
  • must be unique within a control program

Editing Privilege

Preset - Each microblock property has an appropriate privilege or role assigned to it. You can use Global Modify in the i-Vu® interface to find out what the actual privilege is.

Source graphics CAUTION  If you change the Editing Privilege from Preset, the privilege you select will be used for all properties of this microblock, which is not always desirable.

Feedback Delay

You can set an allowable delay between the time a digital output turns on and the time the digital input registers the new status. When the microblock's do input turns on, if the di input does not turn on by the time the feedback delay time expires, the alrm output turns on.

Debounce Time

The Debounce time setting is the amount of time that the di input must remain on or off before it is considered valid. The Debounce time should not be longer than the feedback delay; otherwise, an alarm will be generated each time the equipment starts.

Property Page Text

Show Property Page Text

Check to show this microblock's value on the equipment's Properties page.

Property Page Text

You can edit the microblock description that appears on the Properties page. See "Editing Properties page text using special characters" and "Formatting a microblock property" in Snap Help.