Quality Descriptors

0 (least significant)

For Single Points:
If the StoreDigitalInQual parameter is 1, this bit contains the current point value

For Double Points:
If the StoreDigitalInQual parameter is set this bit contains the lower bit of the point value (DPI)

For Counters:
Overflow or counter carry indication

1

Transient for integer inputs

For Double Points (if the StoreDigitalInQual parameter is 0 ):
Indeterminate / intermediate state for double digital inputs (DDI)

For Double Points (if the StoreDigitalInQual parameter is 1 ):
The upper bit of the point value (DPI)

2

For Double Points (if the StoreDigitalInQual parameter is 0):
Invalid state for double digital inputs (DDI)

3

Blocked

4

Substituted

5

Not topical

6

Invalid

7

Counter adjusted since last reading

8... 12

Counter Sequence number (number from 0 to 31)

13

Quality Descriptor out of date

14

Timestamp was provided by PC, not RTU

15 (most significant)

Timestamp from RTU has "invalid" set.
(This bit is undefined if timestamp is provided by PC, i.e. bit 14 is set.)