French to English Tech/Engineering Automotive / Cars & Trucks test of a continuous measurement flow tester

The document is a study of the performance and measurements (metrology) of the above-mentioned device. It is a competitor product,
and the company is measuring the device against one of its own similar products.


I'm not sure sure what the above abbreviation stands for in the following sentence:

Un étalonnage complémentaire est réalisé avec le CDF sans les conditions standard.

The calibration refers to a flowmeter, at a point in the text where there are a couple of graphs showing the flow measurement differences in percent when there are 'standard conditions' and when there are not.

Any help gratefully received.