NI 9205

[LeeJoongSeon]

hello.

I am leaving a question because I encountered a slight error while using the NI9205 model.

first, I did the H/W wiring as shown in the attached file(image.png).(The com terminal is not connected.)

When measuring voltage in this situation, strange values ​​appear even when power is applied, and strange values ​​appear even when power is not applied. (For example, the Labview screen shows -10[V].)

To resolve this situation, I connected them as shown in Figure 6 and Figure 7 in the second attachment file(NI_9205_Manual), but the same phenomenon occurs.

I am wondering how to make the connections and how to program Labview to measure voltage with a differential signal.

Labview file is attached.

Thanks for reading.

[GerdW]

Hi Lee,

two comments:

1. Please (re)attach your images…
2. I got reasonable readings whenever I connected signals to the NI9205 as was described in the manual. So your wiring might not be correct or the NI9205 module is broken!? (Did you think about ghosting effects on unwired inputs?)

[LeeJoongSeon]

 

Attach images and labview files!

[GerdW]

Hi Lee,

I would NEVER connect the NI9205 to >200Vac sources! (Even with your voltage divide in front of the pins…)

Ever thought about isolated voltage and dedicated current transducers?

Please make a simple test: use a standard alkaline battery (AAA is enough) with ~1.5V voltage and try to measure this using your NI9205: does it show the expected value?

(Any other small DC voltage will work too, from 3V Lithium battery to 5V USB power. In fact anything less than the ±10Vdc measurement range of the NI9205…)

Btw. as you attached the manual you surely read it carefully: where did you connect the COM pin as suggested in figure 6?

(Warning: DON'T attach it to "earth" of your 220Vac power supply! Ask an electrician and your local (human/work) safety responsible before doing any more harm to your DAQ device and the people working with it.)