Counter retrieval - handling NULL values

If wwQualityRule is configured as OPTIMISTIC, NULL data points will not be used in calculation. 0.0 will be used as the starting base value for the query unless the query data starts with a NULL. If the query starts with a NULL, the value change for the cycle is calculated from the first actual value in the cycle, rather than 0.

Otherwise, if any points considered in a cycle have UNCERTAIN quality, the result for that row will also have UNCERTAIN quality. Any cycle that starts or ends in a gap will have a quality detail of 65536.

The quality detail of DOUBTFUL will be used with the counter result for the cycles, if a NULL point is considered for the cycle and the counter result is not NULL.