Quality-String format specification
A TwinCAT Quality string has the following structure: 'Q#vv|ORBSFDCA|s|TB'.
Variable | Representation | Value range | Description |
|---|---|---|---|
Prefix | Q# | ‘Q#‘ | Constant prefix. |
vv | ‘00‘,‘01‘..‘11‘ | Validity. | |
Overflow | O | '0'..'1' | Overflow. |
OutOfRange | R | '0'..'1' | Not in permissible range. |
BadReference | B | '0'..'1' | Incorrect reference. |
Oscilatory | S | '0'..'1' | Oscillating. |
Failure | F | '0'..'1' | Failure. |
OldData | D | '0'..'1' | Data not up to date. |
Inconsistent | C | '0'..'1' | Inconsistent. |
Inaccurate | A | '0'..'1' | Inaccurate. |
s | '0'..'1' | Source (‘0‘:=process, ‘1‘:=replaced). | |
Test | T | '0'..'1' | Test. |
OperatorBlocked | B | '0'..'1' | Operator blocked. |
Coding of the Quality.Validity components:
Value | Validity0 | Validity1 | STRING(2) | Description |
|---|---|---|---|---|
Good | 0 | 0 | ‘00‘ | Good (default value). |
Invalid | 0 | 1 | ‘01‘ | Invalid. |
Reserved | 1 | 0 | ‘10‘ | Reserved. |
Questionable | 1 | 1 | ‘11‘ | Questionable. |
Coding of the Quality.Source components:
Value | Source | STRING(1) | Description |
|---|---|---|---|
Process | 0 | ‘0‘ | Value comes from the process (default value). |
Substituted | 1 | ‘1‘ | Value was replaced. |
Samples
The table below contains strings and the values of the components after conversion to the structured type: ST_AcsiQuality.
STRING(18) | ST_AcsiQuality | Description |
|---|---|---|
'Q#00|00000000|0|00' | STRUCT(0) | All components have the value: 0. |
'Q#01|00000000|1|10' | STRUCT(Validity0:=0, Validity1:=1, Source:=1, Test:=1) | Validity: Invalid. Source: Replaced.Test is set. All other components have the value: 0. |
'Q#11|11000001|0|01' | STRUCT(Validity0:=1, Validity1:=1, Overflow:=1, OutOfRange:=1, Inaccurate:=1, OperatorBlocked:=1) | Validity: Questionable.Overflow, OutOfRange, Inaccurate and OperatorBlocked are set. All other components have the value: 0. |