request IQC or Control chart node to handle data with missing value on the specification.

When there are missing value in any of the samples' control limits. IQC analysis (Enterprise or Interactive module) or Control charts treat samples with missing value as a different set and errors out that missing data in sets even though no sets are identified in the data.

1. The error message could be updated to point out there is missing data in specification limits in general since it could cause confusion to the users when there are no sets identified. 

2. We have option to calculate the control limits when missing data are present in the SPC chart node, but it is not seen in the IQC analysis configuration, R&D could evaluate if this need be added.

3. Request that control charts be plotted even when missing control limits are present for part of the samples. And the control line should be broken for those, i.e. not control limits below or above to reflect that the fact that control limit are missing for this.