Choosing bias resistors for differential voltage measurement from changing impedence sources

[Henrik_Volkers]

I strongly recomment that you do tests about ghosting of the multiplexed input signals. Since your source impedance is in the 1k to 5k region and your voltage inputs a like a sawtooth the 'jump from the highest to lowest voltage is the one most critical.

Choosing the lowest possible samplerate, using buffers or reading the critical channels twice (the channel list for scanning can be arbitairy) can help if you run into trouble.

 Here the diagram of page two of the spec

 

[ramcd]

Certainly I am working in the specs of the DAQ box. I am setting the interchannel delay of about 150 micro-sec, so that even 10 kohm impedance have ample time to settle to accuracy of the DAQ. Additionally, the voltage swings between the channels is not very large. What additional things need to be kept in mind to minimize ghosting?

thanks Henrik