differential measure of 6280

[tthree]

I have PCI-6280. Can I measure or capature the analog wave form range 0-18V? Can I use differential mode?

Thanks, TT

[nayer]

Hi TT,

According to specification on this card you cannot measure the signal which ranges form 0-18V. But you can connect two 1K resistors in series and measure the voltage of second resistor.

Cheers

NI-khil

[tthree]

Thanks, Actually, it is a waveform range fron 0 - 18V. Do you think NI 6280 build in common-mode voltage?

http://zone.ni.com/devzone/cda/tut/p/id/3344#toc2

Or I have to build some buffer to drive to -9 to +9V..

Thanks again.

TT

[Henrik_Volkers]

Just to add a note to the voltage divider proposed by NI-khil:

This will work for DC only!! 

When measuring AC Voltages the resistors get impedances and together with the input IMPEDANCE you have to match these too!

(Ever wonder what's that small srew on a 10:1 probe of a scope is good for? )

[nayer]

Hello there,

Henrik is absolutely correct; as mentioned you can use the 10x probe, but generally the probes are designed for the scopes or digitized input which has termination impedance of Ohm which is not be the case with the DAQ card. And as far as your previous question is concern you would need to make a buffer to make the voltage look like it is +/-9 V

Cheers

NI-khil

[tthree]

Thanks, TT