Quality codes
The quality code measures the quality of a value when it is transferred from a CPU via the connector to IIH Essentials.
There are three different types of qualities:
- GOOD
- UNCERTAIN
- BAD
IIH Essentials stores all values, regardless of their quality, and forwards them to other apps. In the respective apps, the values are then taken into account or ignored according to their quality.
If the quality is GOOD or UNCERTAIN, then the values are taken fully into account in the app.
What does it mean if the value has the quality BAD:
- This value is not taken into account when calculating KPIs, e.g. in Performance Insight or Energy Manager.
- The value is also saved when the raw data is saved in an app.
WinCC UA Standard is used to mark the quality of the values.
From bits 6 and 7 you can read out the quality which a value has. From bits 2 to 5 you can get more information about the quality.
Quality bits 6 and 7
| Quality code | Quality | Description |
|---|---|---|
| 0 | BAD | The value is not reliable. You can read out the reasons for this from the bits of sub-status. |
| 1 | UNCERTAIN | The quality of the value is worse than usual. It might still be possible to use the value. You can read out the reasons for this from the bits of sub-status. |
| 2 | GOOD (non-cascade) | The quality of the value is good. |
| 3 | GOOD (cascade) | The quality of the value is good and can be used as a control. |
BAD + Sub-status bits 2 to 5
| Quality code | Quality | Description |
|---|---|---|
| 0 | Non-specific | There is no information available as to why the value is BAD quality. |
| 1 | Configuration error | The value is not useful due to some inconsistencies in the configuration. |
| 2 | Not connected | The value is not reliable because the connection to the provider, e.g. to the CPU, was terminated. |
| 4 | Sensor failure | The value is not meaningful because it cannot be converted. |
| 5 | No communication, with last usable value | The value is not meaningful because communication with the data source has failed. However, the last known value is available. |
| 6 | No communication, no usable value | The value is not meaningful because communication with the data source failed or was not set up. |
| 7 | Out of service | The value is not reliable because the provider is not active. |
UNCERTAIN + Sub-status bits 2 to 5
| Quality code | Quality | Description |
|---|---|---|
| 0 | Non-specific | There is no information available as to why the value is UNCERTAIN quality. |
| 1 | Last usable value | The connection to the data source still exists, but the data source no longer updates the value. |
| 2 | Substitute value | A predefined value is used because the value is invalid due to communication problems. |
| 3 | Initial value | A predefined value is used. |
| 5 | Range violation | The value is outside the specified limits (min/max values) |
| 6 | Sub-normal | A value derived from multiple values has less than the required number of good sources. |
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