08-28-2020 02:10 PM
I am new to NI DAQ units and I am trying to get a feel for taking basic measurements. I setup a 4 resistor voltage divider between AIGND >>> AI0 >>> AI1 >>> AI2 >>> AI3 I am giving the divider 8.00V into 100K 1% resistors.
I setup 5 channels for voltage and Referenced Single-Ended sampling at 1Hz and my read voltages are as follows.
CH0 - 1.877V (Value on scope 1.87V)
CH1 - 3.549V (Value on scope 3.51V)
CH2 - 5.364V (Value on scope 5.50V)
CH3 - 7.989V (Value on scope 7.93V)
CH4 - 7.954V (Value on scope ~30mV)
Why do I get voltage on channel 4 when it is not hooked up and the scope does not read anything on that input. AI12 also does this and others. It seems any unconnected channel that is next to an active channel picks up the signal and I am worried that if I need to use all 16 channels that the data will not be accurate.
Please advise.
08-31-2020 11:08 AM
So I think my unit is damaged. When trying to measure LIFEPO4 battery voltage on AI0 I am getting -8.9V my DMM shows -3.36V across the terminals so something is clearly wrong. I will have to contact service and have the unit looked at.