Configure I/O as Read-only

Select Read in the I/O parameters area. Define an input source by using I/O auto-assignment, by typing in the reference string, or by clicking the Attribute Browser button at the right.

• Use I/O auto-assignment to prepare the input source for automatic assignment to a configured Device Integration (DI) object or other data source. For information about using I/O auto-assignment, see Using I/O Auto Assignment.

  Important: If the InputSource attribute is locked in the parent template, the attribute cannot be updated with the resolved reference when the object is deployed, and the run-time value will be "---Auto---".

• Use the Attribute Browser to select an attribute and automatically insert the correct reference string for that attribute. For more information about using the Attribute Browser, see Reference Objects Using the Galaxy Browser.

• If you are configuring an I/O attribute for use with the Telemetry Server, see Configure I/O for Use with AVEVA Telemetry Server Communication Drivers for additional information.

  

You can add multiple Read (input) I/O Features to an object. However, you cannot add a Read/Write (InputOutput) I/O Feature to an attribute that already has either a Read or a Write (output) I/O Feature. Arrays are not supported.

Note: Lockable attributes can be configured with a Read I/O Feature, but they only function correctly during run time if the configured attribute is unlocked.

If the data types of the attribute and its I/O source attributes are the same, they are set to equal values according to the object’s execution rate. If the two attributes are different data types, coercion rules are applied.

If coercion fails or the input value is out of the attribute’s range, quality for the configured attribute is set to Bad. Otherwise, the configured attribute quality matches the source attribute. When the object is Off Scan, quality is always Bad and user sets are accepted.

Attributes configured with a Read I/O Feature are not protected by their security classification. The only enforced security specifies if an IDE user can edit or add features to the object. A Read I/O Feature can be added to a template or instance. If added to a template, the existence of the Read I/O Feature is automatically locked in derived objects.