Overriding [OPC]CacheRead

You can override the value in [OPC]CacheRead for a particular tag by suffixing the tag name with:

The delimeter "!"

The letter C or D, as follows:

• <Tag Name>!C - The tag value returned will be the cache value at the time of the read.

• <Tag Name>!D - A refresh of the tag value is forced before it is returned.

Examples:

• Tag1!D - Forces a refresh of Tag1 before the value is returned.

• Tag!C - The last known cache value of Tag2 is returned.

When the tag qualifiers C and D are used with other OPC qualifiers (see Timestamp and Quality Support), they must appear last.

Example:

• Tag3QC - Tag3 is associated with a quality tag and the last known value of Tag3 will be returned.