Each data point or value reported by the outstation can have an associated quality flag that indicates its status. These quality flags are essential for the master station to interpret the data correctly. Quality flag is BYTE data type where each bit level represents different status in each object group. Refer below table for quality flag bit wise information.
|
Quality flag |
Online |
Restart |
Comm lost |
Remote forced |
Local forced |
Chatter filter |
Over range |
e |
State |
|
|---|---|---|---|---|---|---|---|---|---|---|
|
Binary input |
00 |
01 |
02 |
03 |
04 |
05 |
NA |
NA |
NA |
07 |
|
Double binary |
00 |
01 |
02 |
03 |
04 |
05 |
NA |
NA |
NA |
06- 07 |
|
Binary output |
00 |
01 |
02 |
03 |
04 |
NA |
NA |
NA |
NA |
07 |
|
Counter input |
00 |
01 |
02 |
03 |
04 |
NA |
NA |
06 |
NA |
NA |
|
Frozen counter |
00 |
01 |
02 |
03 |
04 |
NA |
NA |
06 |
NA |
NA |
|
Analog input |
00 |
01 |
02 |
03 |
04 |
NA |
05 |
NA |
06 |
NA |
|
Frozen analog |
00 |
01 |
02 |
03 |
04 |
NA |
05 |
NA |
06 |
NA |
|
Analog output |
00 |
01 |
02 |
03 |
04 |
NA |
05 |
NA |
06 |
NA |
NA – Not applicable.
Description of the quality flags used.
-
Online (flag bit 0): Indicates whether the data point is currently online and active. If this flag is not set, the data point might be offline or inactive.
-
Restart (flag bit 1): Shows that the device or system has recently restarted. If this flag is not set, no restart or reset has occurred.
-
Communications lost (flag bit 2): Indicates that communication with the data point was lost. This flag is crucial for understanding data gaps or communication issues.
-
Remote forced data (flag bit 3): It signifies that the data point value was forced or overridden remotely. This can be useful in situations where manual intervention has occurred.
-
Local forced data (flag bit 4): It signifies that the data point value was forced or overridden locally at the outstation.
-
Chatter filter: It shows that the data point is experiencing rapid state changes, and a chatter filter is being applied to stabilize the readings.
-
Over-range (flag bit 5): It indicates that the data value is over range. This flag helps identify measurement anomalies or sensor issues.
-
Reference error (flag bit 6): It indicates a reference issue with the data point, such as calibration problems.
-
State (flag bit 7): It provides the current state of the data. It is reserved as “0”.