Quality of data value
Quality
indicates the quality of the daitem
object’s Value
property as a character vector.
You can use the Quality
property to determine if a value is
useful or not.
The Quality
is made up of a major quality, a substatus, and an
optional limit status, arranged as a character vector 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 |
---|---|
|
The value is not useful for reasons indicated by the substatus. |
|
The value is of good quality. |
|
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.
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 |
|
Data type |
character vector |
Values |
The default value is |