The first step is to install an accurate and suitable Compressed air Flow meter at all essential points to obtain reliable measurement data, e.g. downstream of each Compressor. The flow meter is installed directly in the main line, at the outlet of the Compressor. The first step is to record the compressed air consumption in the main line, ideally using an intelligent Data logger, while simultaneously measuring the Compressor's power consumption.

Measuring the power consumption [kWh] and the delivery rate of the Compressor [^m3] at the same time makes it possible to determine the specific power of the Compressor in [^kWh/m3]. The specific power gives an indication of how much energy is required to produce one cubic metre of Compressed air. As energy costs make up the largest proportion of the total costs of a compressed air system, it is advisable to record the values described in order to take action if Compressed air generation becomes inefficient over time.

The biggest challenge in Measuring the direct Delivery rate (or FAD) of a compressed air system is the harsh conditions under which the Flow meter must operate reliably and the high Velocities that can occur and must be intercepted.

The Temperature of the Compressed air directly at the outlet of the Compressor is usually higher than with a standard Flow measurement, and the Degree of humidity is also almost saturated, meaning that condensation can occur. These types of conditions are not suitable for every Measuring principle.

The VD500 flow meter measures according to the differential pressure principle and allows measuring up to 600 m/s. The device is also suitable for hot and humid conditions. Measuring directly at the outlet of the Compressor up to 180°C is possible with the VD500.