Handle of null values in CSV files

The value to insert can be a NULL.

If the OPC Quality in the CSV file is between 0 to 63, then:

• The NULL value is stored.

• The Quality Detail is set to 249 (not a number).

• The OPC Quality is what was specified in the CSV file.

If the OPC Quality in the CSV file is greater than 63, then:

• The value that was specified in the CSV file is stored.

• The Quality Detail is set to 192 (unless the value specified is NULL in the CSV file, in which case the Quality Detail is set to 249).

• The OPC Quality is what was specified in the CSV file (unless the value specified is NULL in the CSV file).

If the value is not NULL, but the OPC Quality is less than 63, then:

• A NULL value is stored.

• The Quality Detail is set to 249 (not a number).

• The OPC Quality is what was specified in the CSV file.