QualityGetPart

Extracts a requested part of the quality value from a variable tag's quality item.

Syntax

QualityGetPart(QUALITY quality, INT part)

quality:

Specifies the quality variable.

part:

The part to extract:

0 – The General Quality value

1 – Quality Substatus value

2 - The Quality Limit value

3 - The Extended Quality Substatus value

4 – The Tag Status Override flag

5 – The Tag Status Control Inhibit flag

6 - The DataSource error code

7 – The OPC Quality (General + Substatus + Limit)

Return Value

The value of the requested Quality part (see tables below), or -1 if error.

Part 0 - General Quality Values

Part 1 - Quality Substatus Values

This part returns a value from one of the following susbstatus groups:

• QUAL_BAD
• QUAL_UNCR (uncertain)
• QUAL_GOOD

To determine which substatus group the return value is from, you need to initially call the General Quality Value (part = 0).

• Quality Substatus Values - QUAL_BAD

Cicode label name	Value	Description
QUAL_BAD_NON_SPECIFIC	0x00	The value is bad but no specific reason is known.
QUAL_BAD_CONFIGURATION_ERROR	0x01	There is some server-specific incorrect configuration. For example, the item in question has been deleted from the configuration.
QUAL_BAD_NOT_CONNECTED	0x02	The input is necessary to be logically connected to something but is not. This quality may reflect the fact that no value is available at this time, for reasons like the value may not have been provided by the data source.
QUAL_BAD_DEVICE_FAILURE	0x03	An inoperative device has been detected.
QUAL_BAD_SENSOR_FAILURE	0x04	An inoperative sensor has been detected (the ‘Limits’ field can provide additional diagnostic information in some situations).
QUAL_BAD_LAST_KNOWN_VALUE	0x05	Communication has been lost, however, the last known value is available. The age of the value may be determined from the TIMESTAMP in the OPCITEMSTATE.
QUAL_BAD_COMM_FAILURE	0x06	Communication has been lost. There is no last known value available.
QUAL_BAD_OUT_OF_SERVICE	0x07	The block is off scan or otherwise locked. This quality is also used when the active state of the item or the group containing the item is InActive.
QUAL_BAD_WAITING_FOR_INI_DATA	0x08	After items are added to a group, it may take some time for the server to actually obtain values for these items. In such cases, the client might perform a read (from cache), or establish a ConnectionPoint based subscription and/or execute a refresh on such a subscription before the values are available. This substatus is only available from OPC DA 3.0 or newer servers.

• Quality Substatus Values - QUAL_UNCR

Cicode label name	Value	Description
QUAL_UNCR_NON_SPECIFIC	0x00	The value is uncertain but no specific reason is known.
QUAL_UNCR_LAST_USABLE_VALUE	0x01	Whatever was writing this value has stopped doing so. Regard the returned value as ‘stale’. This differs from a BAD value with Substatus 5 (0x14) (Last Known Value). This status is associated specifically with a detectable communication error on a ‘fetched’ value and indicates the failure of some external source to ‘put’ something into the value within an acceptable period of time. The age of the value can be determined from the TIMESTAMP in OPCITEMSTATE.
QUAL_UNCR_SENSOR_NOT_ACCURATE	0x04	Either the value has ‘pegged’ at one of the sensor limits (in which case, set the limit field to 1 or 2) or the sensor is otherwise known to be out of calibration via some form of internal diagnostics (in which case,set the limit field to 0).
QUAL_UNCR_ENG_UNIT_EXCEEDED	0x05	The returned value is outside the limits defined for this parameter. In this case the Limits field indicates which limit has been exceeded but does NOT necessarily imply that the value cannot move farther out of range.
QUAL_UNCR_SUBNORMAL	0x06	The value is derived from multiple sources and has less than the necessary number of Good sources.

• Quality Substatus Values - QUAL_GOOD

Cicode label name	Value	Description
QUAL_GOOD_NON_SPECIFIC	0x00	The value is good. There are no special conditions.
QUAL_GOOD_LOCAL_OVERRIDE	0x06	The value has been Overridden. Typically this is means the input has been disconnected and a manually entered value has been "forced".

Part 2 - Quality Limit Values

Part 3 - Extended Quality Substatus Values

Part 4 - Tag Status Values - Override Flag

Part 5 - Tag Status Values - Control Inhibit Flag

Related Functions

QualityIsBad, QualityIsContolInhibit, QualityIsGood, QualityIsOverride, QualityIsUncertain, QualitySetPart, QualityToStr, QualityCreate

Example

INT qualityGeneral;
qualityGeneral = QualityGetPart(Tag1.Field.Q, 0);

See Also

Quality Functions

Published June 2018