| OPC Toolbox™ | |
Quality indicates the quality of the daitem object's Value property as a string. You can use the Quality property to determine if a value is useful or not.
The Quality string is made up of a major quality string, a substatus string, and an optional limit status string, arranged in the format 'Major: Substatus: Limit status'. The limit status part is omitted if the value is not limited. The major quality can be one of the following values:
Value | Description |
|---|---|
Bad | The value is not useful for reasons indicated by the Substatus. |
Good | The value is of good quality. |
Uncertain | The quality of the value is uncertain for reasons indicated by the Substatus. |
For a list of substatus and limit status values and their interpretations, consult OPC Quality Strings.
Quality is updated when you perform a read operation using read or readasync, or when a subscription callback occurs. Quality is also returned during a synchronous read operation.
Access | Read-only |
Applies to | daitem |
Data type | string |
Values | The default value is 'Bad: Out of Service'. |
QualityID, Subscription, TimeStamp, UpdateRate, Value
| Parent | QualityID | |
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