When loading a data file and zooming in a specific portion, we can see that the curves don't overlap completely. There are three major differences. First we can observe the differences in amplitude. This comes from the fact that this sensor is already quite old already, and the calibration has period expired, therefore the voltage output might not be exact.

Secondly, we can see that the RS232 data has a delay. This is quite normal, since the data has to be transmitted through a slow digital interface. A well-written plug-in (a driver for the device inside DEWESoft) can compensate for this delay. Also, the rate of data flow is much slower with RS232 than with the analog.

Finally, we can see that the voltage and current output doesn't output the negative mass flow, even though the sensor supports it.

Analysis

So, what is better to use, voltage or digital interface? It would be incorrect to state that it is ALWAYS better to use one interface, because this depends a lot on the sensor itself. First, the user should look how the sensor is built. If it is an analog sensor in the first place and the voltage output is the main output, it is logical to use this output. The drawbacks for using analog output is that we can have noise, problems caused by long cables and the voltage inputs needs to be recalibrated over time.

If the sensors have a digital interface as the, default and they have DA converters to make analog output, then it makes no sense to use this analog interface since this results in nothing but losses. Of course, the use a of digital interface requires some extra work in writing the drivers, if the interface is not standard (like CAN bus, for example).