The majority of data which is contained within the variable tag is represented as an element which includes the items "Value", “ValueTimestamp”, “Quality”, “QualityTimestamp” and "Timestamp". With the exception of "Quality" these items are absolutes of a single value. However the 'Quality" item has several layers of information within it. These layers of information are covered by the following categories:
The primary layer identifies the General Quality Values.
| Cicode label name | Value | Description |
|---|---|---|
| QUAL_BAD | 0x00 | Value is not useful for reasons indicated by the Substatus Bit Field. |
| QUAL_UNCR | 0x01 | The Quality of the value is uncertain for reasons indicated by the Substatus Bit Field. |
| QUAL_GOOD | 0x03 | The Quality of the value is Good. |
These can be accessed from a text object on a graphics page at runtime or with Cicode using the QualityGetPart Cicode function and the necessary Part parameter.
Within each of these quality values is a second, substatus layer, and a third extended substatus layer. These layers of information listed below can also be accessed using the QualityGetPart Cicode function.
There is also the additional informational value of "Quality Limit" and "Tag Status" accessed using the QualityGetPart Cicode function or the appropriate function shown below.
Quality Limit
| Cicode label name | Value | Description |
|---|---|---|
| QUAL_LIMITED_NOT_LIMITED | 0x0 | The value is free to move up and down. |
| QUAL_LIMITED_LOW | 0x1 | The value has ‘pegged’ at some lower limit. |
| QUAL_LIMITED_HIGH | 0x2 | The value has ‘pegged’ at some high limit. |
| QUAL_LIMITED_CONSTANT | 0x3 | The value is a constant and cannot move. |
Quality Tag Status
| Cicode label name | Value | Description |
|---|---|---|
| QTS_OVERRIDE | 0x01 | The tag is in Override mode. |
| QTS_CONTROL_INHIBIT | 0x02 | The tag is in Control Inhibit Mode. |