NI6229 Channel range configuration

[bhyy]

I have a problem when I use the PCI_6229.The first channel collects millivolts,and the remaining channels collect  cell monomer voltage.So I want to set the first channel range is 0~1v,and the remaining channels range is 0~10v.How do I configure the Card in this situation?

[GerdW]

Hi bhyy,

have you tried to configure the DAQmxCreateVirtualChannel function for each channel as needed?

[mcduff]

According to the spec sheet, the ADC is muxed; thus all channel gains need to be the same, if I understand the question correctly.

mcduff

[Bob_Schor]

Build a simple x1000 pre-amp for Channel 1.

Bob Schor

[Kevin_Price · Accepted solution]

You *can* configure distinct gains / ranges for the different channels.  Here's a snippet to illustrate GerdW's suggestion in msg #2.

-Kevin P

[BertMcMahan]

Kevin_price is right, you can set different ranges per channel, BUT be aware you might get some ghosting after switching between channels, depending on your circuit's specifics.

I had an application where I needed to measure 15 channels in the 0-0.1V range, then a 16th in the 0-10V range, and I would see higher voltage than was real after scanning the 10V channel. (Note I was also scanning very quickly- a slower rate will help a lot).

Basically, if the muxed ADC is reading 9 V on something, then it needs to read 0.01 V, it will need some time to "bleed" down to that level. IIRC I was reading at ~50 kHz which resulted in ghosting on the first few channels. Just something to keep in mind.