DAC vs VS

2 posts / 0 new

Thu, 04/08/2021 - 23:55

djhedges

DAC vs VS

I'm looking to read values from a pair of Honeywell pressure sensors. The sensor has 3 pins, 0V, 5V and Signal. My plan was to use AIN2 & AIN3 to read the signal voltage while connecting the 0V to the GND terminal near these AIN terminals. I'm torn on what to use for the 5V reference. Should I use DAC0? or VS? If not VS what is the purpose of VS?

https://www.motec.com.au/filedownload.php/?docid=2459

Thanks

Fri, 04/09/2021 - 11:04

LabJack Support

I would recommend using the

I would recommend using the DAC output, it will be better regulated than VS. I would still recommend measuring the DAC output when connected to your sensor to get the actual voltage drop.

VS is 5V USB power, and it is not regulated well enough for us to recommend it with ratiometric sensors. For sensors that are not ratiometric and take 5V power, VS is useful because you can source a lot more current from it than any other ports on our devices. Please see the U3 appendix for relevant specifications:

https://labjack.com/support/datasheets/u3/appendix-a