Extremely smaller analog input signal than actual one using USB-6211

[lovelaser]

Hello! 

I face trouble that USB-6211 shows the extremely smaller analog input signal than actual one. 

I bought USB-6211, and tried to use it in order to measure an analog voltage signal using NI DAQ Express. 

AI0 and AI8 of USB-6211 was connected to BNC jack of a function generator. 

I'll attach the figure of wiring.  

The function generator creates a squre wave. 

An oscilloscope measured its frequency and peak-topeak voltage which were 200 Hz and 20 V at high Z condition. 

However, NI DAQ Express indicates peak-to-peak voltage ~0.2 V (please see attached image). 

Wold you like to tell me why such a value was measured? 

Thak you for your attention! 🙂 

[lovelaser]

Sorry, AI0+ and AI0- were mistype.
AI0 and AI8 are correct numbers.

[lovelaser · Accepted solution]

Hello.

I could solve the problem of the extremely small signals from an analog input chanels.
We have to turn right the screw of the terminal to clamp the wire, but I turned left to fix it.
When even turning the screw left, the wire can be clamped, but the contact between the wire and the terminal seems to be unsufficient.
The bad contact between the wire and the terminal made signals indeed small.

Thank you for our attention. 😁