Flow probe and 9215

[drowe84]

Hi,

I was looking for some advice on connecting a flow probe (Vectrino https://www.nortekgroup.com/assets/software/N3015-030-Comprehensive-Manual-Velocimeters_1118.pdf pg 92, section 4.2 for Analog Outputs) to a NI 9215 for voltage input.

The probe can provide output 0-5V, yielding 2.5 V at zero flow.

I tried two configurations with the NI 9215 on NI MAX.

i) Grounded Differential Connection: AI+ (port 2) connected to X probe terminal block (see attached photo, probe_terminal) and COM (port #9) connected to GND terminal (see attached photo, probe_terminal).

ii) Single-ended connection: - AI+ (port 2) connected to X probe terminal block. AI- (port 3) and COM (port #9) connected to GND terminal.

I've tested both cases on NI MAX and am only managing to extract mV (see test_panel screenshot)

For reference, the output velocity range of the flow probe can be tuned to scale with the voltage output. As per the screenshot (probe_AO), I have selected a small velocity range +/- 0.3 m/s with a mean flow speed of approx 0.2-0.3 m/s. In both cases, I can only read mV so something seems to be wrong.

Is anybody able to advise on where I may be going wrong or something that I may have missed?

Thanks in advance

Daniel

edit: I realise that I posted this in the wrong group

[drowe84 · Accepted solution]

Solved. I found a wiring issue to ground.