# Understanding Pressure specifications: % of Full Scale vs % of Full Span and % of Full Range

There is some confusion over the meaning of terms used in specifications for Fluke handheld pressure calibrators. This is a brief explanation of these terms.

Glossary :

% of Full scale : It's a two step process one calculation for Pressure and one calculation for Vacuum.

Here is an example the Fluke-750R06 it's a gauge that measures both pressure and vacuum, and the range is from -12psi to 100psi. The 1-year specification is +/-0.02% of Full Scale, if you are measuring pressure the accuracy is (100psi x 0.02%= 0.02psi) and if you are measuring vacuum the accuracy is (-12psi x 0.02%= .0024psi)

Here is another example the Fluke-750RD6 it's a gauge that measures pressure only, and the range is from 0psi to 100psi Full Scale. The 1-year specification is +/-0.02%  (100psi x 0.02%= 0.02psi).

% of Range and % of Span are two terms that mean the same thing: If the Pressure Calibrator has both Pressure and Vacuum you add them together before calculating the specifications and if it's Pressure only you use that parameter to calculate the specifications.

Here is an example the Fluke-750PD06 it's a gauge that measures both Pressure and Vacuum, and the range is from -15psi to 100psi Full Span. The 1-year specification is +/-0.035%  (115psi x 0.035%= 0.040psi).

Here is another example the Fluke-750P06 it's a gauge that only measures pressure, and the range is from 0 to 100psi Full Span. The 1-year specification is +/-0.035%  (100psi x 0.035%= 0.035psi).

Specification used on our Models :

Fluke 717, 718 and 719 : % of Full Range. Includes negative side.

Fluke 719Pro, 721 and 729 : % of Full Scale, you need to calculate two calculations one for positive uncertainty and one for negative uncertainty

700P pressure modules : % of Full Span. Includes negative side.

750P pressure modules : % of Full Span includes negative side,

750R pressure modules: Reference class modules are  % of Full Scale, you need to calculate two calculations one for positive uncertainty and one for negative uncertainty.

700G gauges : % of Full Scale, you need to calculate two calculations one for positive uncertainty and one for negative uncertainty.

Example below is from 750P Technical Data sheet    