Using CitectSCADA > Tagging Process Variables > Tag Extensions > The Quality Tag Element

The Quality Tag Element

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.