Writing Tag Values | System Model

System Model > Variable Tags > Refer to Variable Tags > Write to a Tag Value

Write to a Tag Value

The tag elements which have read/write access can be modified. However, these elements can only be updated as a whole; writes to an individual element item is not allowed.

The following table shows the result of writing to each of the tag elements:

Element Name	Write allowed	Write Result
Not specified (unqualified tag reference)	Yes	Write to the Field element and propagate the value to the I/O device.
Field	Yes	Write to the Field element and propagate the value to the I/O device.
Valid	No	Will not succeed.
Override	Yes	Write to the Override element.
Override Mode	Yes	Write to the Override Mode element. See the appropriate function references for the available override mode values. Note: When the tag is in Override mode, an unqualified tag reference will refer to the Override element.
Control Mode	Yes	Write to the Control Mode element The Value item can be one of the following: 0 – Control inhibit mode is Off. 1 – Control inhibit mode is On. Note: When Control inhibit mode is On, writing to the Field element is prohibited.
Tag Status	No	Will not succeed.

If you determine that the tag value is incorrect because of a sensor or communication interruption, the tag value may need to be overridden. The Override element tag element is used to store the overridden tag value. For further information, refer to Set a Tag to Override Mode.