Chemistry Unit Consistency

Different data sources may give results in different units; sometimes these will be equivalent (eg mg/l and ppm) or sometimes they will require a conversion to obtain consistency (eg mg/l and ug/l).

ESdat allows the data to be imported and stored in the original units and converts data to consistent units upon output.  This functionality enables direct comparison of data from different sources and in different units.  The selected units are set on a per compound basis.

In Access versions the units are specified in the zRef_Chemistry_Lookup table.  In the Access version each project references it's own internal list of units to be used.

In the SQL Server version a single central Chemistry Lookup table is used, but a number of "Profiles" can be be generated with different compound units and grouping for each profile.   In the SQL Server version the units are specified in the zRef_Chemistry_Lookup_Profiles table.

Chemistry Unit Conversions

Sometimes a required conversion may not be present with the database.  If this is the case the data will not be output (it will be "Missing").  This is typically noticed when outputting a Chemistry Output Table.

ESdat indicates this problem in two spots:

1. In the Chemistry QA Reports, and

2. The "Check Units" button in the main ESdat screen will turn red.

The user can resolve the problem by clicking the "Check Units" button and either adding the required conversion to the database or changing the Output Unit.

Alternatively, conversions can  be added to the "zRef_ConvertUnits" table.