NI 9205 Differential measurement: channel configuration

[shohag.mech]

Hello

I am using NI chasis cDAQ:9188: slot 1: NI 9237 & slot 8: NI 9205. Actually I am interested for differential measurement by NI 9205. So for I know by reading different posts in this forum that: for differential meassurement number of channel reduces to 16 instead of 32. When i go for acquire signal>>DAQ acquire>> analog input>> voltage : a window pops up showing 32 channels to selest one (the figure 1). The number of channels should be 16 instead of 32. Please correct me If i am wrong. I tried NI MAX to configure terminal and selected the differential option (figure 2) but still i am getting 32 channels. Is there any setting that need to be adjusted for differential measurement. 

[shohag.mech]

ANY IDEA HOW COULD I GET ACCESS TO THIS MODULE CONFIGURATION ??????

[Freelion8]

If you use differential mode in 9205 settings, channels are paired together as shown below;

AO0 and  AO8

AO1 and AO9

AO2 and AO10

AO3 and AO11

AO4 and AO12

AO5 and AO13

AO6 and AO14

AO7 and AO15

AO16 and AO24

AO17 and AO25

AO18 and AO26

AO19 and AO27

AO20 and AO28

AO21 and AO29

AO22 and AO30

AO23 and AO31

If you use channels on the left side, the channels on the right side will automatically be assigned so you need to physically wire your input signal (+) to the channels on the left and input signal (-) to the channels on the right. For instance, if you configure AO0 as differential, AO8 will be assigned to it so do not configure AO8.

[shohag.mech]

Thanks for the guideline. I am gonna hook up my sensors and change the channel configuration as you mentioned. I will let you know if it works. 

[Freelion8]

Please let me know, also there is a little correction, I labeled channels as AO# (Analog Output) but it was supposed to be AI#( Analog Input) since NI 9205 is an analog input module. Sorry for the confusion, hope this solution helps.

[Dargm]

HI,

Anyone know if you can mix input configurations on the NI 9205, like have one channel configured for DIFF, and the remaining 30 RSE. Also , can you specify different input ranges to different channels. What I am getting at, does the configuration of all the channels on a NI 9205 have to be the same, or can it be set on a per channel basis ?

[Dennis_Knutson]

You can mix and match anyway you want. Just be aware that a diff configuration uses two channels. You can place your DAQmx configure channel inside a for loop and pass in arrays for the different settings.

[spikesmike]

I am having a problem with a 9205 module. I configured it for 16 Ch differential measurements. I can only get readings on the first 4 channels. I have replaced the module suspecting it to be bad, but no dice.

Any suggestions?

[hfarley2]

Hi spikesmike,

How exactly are you configuring the 9205 module. Are you doing this in LabVIEW? If so could you post your code so we can make sure you are configuring it properly? If you interface with the device in a NI-MAX test panel can you get readings on all 16 differential channels?

Best,

hfar2

[spikesmike]

Thanks for your reply. You are right about the configuration. I was configuring the 9205 in Labview, but I messed up.
I made the mistake of setting it up like sinlgle ended and not differential. More specifically, I was putting channels

on the (-) inputs, rather than skipping over a block of (-) inputs and picking up my next set of channels starting with

channel 16. A friend of mine caught this. I should have known better.

Thanks again!