acquiring data

[gangaputra]

HI all

I am using PCI 6225 & SCB 68 to acquire data from six channels,,,i have used pin numbers 68, 34,33,66,65,31 as the inputs and pin 67 as ground. when i give a voltage at only one channel it osscilates between the given voltage i.e if 2v is given the graph shows value between -2 & 2. when i give the voltage in only one channel all the other are also some amount of voltage. when others should be at zero. i have attached the pic.By the way i am using labview signal express to generate the waveform and other stuff.

[Dennis_Knutson]

You've connecedt AI0, AI1, AI2, AI8, AI9, and AI10. If you are using differential mode, those are the correct pins but that would mean you only have 3 channels and are those correct from the source? From your image, I can't tell whether you are using diff, sre, or nrse. Can you provide that information? If sre, it might be simpler for you to use consecutive channels.

Also, what you are seeing on unconnected channels is expected. Search the forum for 'ghosting'.

[gangaputra]

i am using sre .

thank you very much

rgds

Rajan

[gangaputra]

hi dennis

if i am using in sre mode you said that i should use in consecutive mode ,,,but in between there is ground,,,so wont it be a problem??

thank you very much

rgds

Rajan

[Marco_Brauner]

Hi, to get this closed:

The easiest way to measure, let´s say 4 channels, in SRE-Mode would be to connect your wires to AI0 - AI3 (just an example)
and to use one ore more of the analog ground- terminals for the ground wires. This would be the setup with the least interchannel-delay
caused by multiplexing the channels.


M. Brauner NIG

[gangaputra]

thank you very much brauner.

rgds

Rajan