nois rading

[bakilalshami@motorola.com]

Hi all,

I am using NI61150 to sample 25KHz signal using channel 1. I made sure that may daq configuration is correct by compare it with other teams who used NI 61150 before. Also, I traced the signal to channel one to make sure it's there. The problem I am facing is: every time I do reading I receive noise between -700 mV to 900 mV. Do you have any suggestions, also, do you know about a self test software of NI 61150 that I can use.

my sampling rate is .0000003 number of samples are 4096S.

[bakilalshami@motorola.com]

Hi all,

I am using NI61150 to sample 25KHz signal using channel 1. I made sure that may daq configuration is correct by compare it with other teams who used NI 61150 before. Also, I traced the signal to channel one to make sure it's there. The problem I am facing is: every time I do reading I receive noise between -700 mV to 900 mV. Do you have any suggestions, also, do you know about a self test software of NI 61150 that I can use.

my sampling rate is .0000003 number of samples are 4096S.

[Travis_W]

I'm assuming you mean the PCI-6250 when you say "NI61150"

If you are using this card, you will need to have the NI-DAQmx driver, which comes with Measurement and Automation Explorer(MAX).  I suggest you use this utility to test your card and your signals.

To do a self test:
1) Open MAX
2) Expand "Devices and Interfaces" then "NI-DAQmx Devices"
3) Right click on your card and choose to "Self-Test"

To measure your signals:
1) Right click on "Data Neighborhood" and select "Create New..." and choose "NI-DAQmx Task"
2) Configure the parameters that it prompts from you (I recommend differential input and continous timing at >100kHz rate)
3) To test, click the "Test" button on the top of the screen.

I highly recommned using Differential Input configuration for superior noise rejection.  This will use 2 pins to measure the signal instead of just one (channels 1 and 9).

[bakilalshami@motorola.com]

Sorry I meant NI PXI-6115, Is NI-DAQmx driver for PCI PCI-6250 same as PXI-6115

Thank you,

[Travis_W]

Actually the 6115 will work with either Traditional NI-DAQ or with NI-DAQmx.  Both of these drivers come with MAX.  You can find out which version of this driver you have by expanding the software tree in MAX and clicking on where it says NI-DAQ X.X.

NI-DAQmx 7.X will have the self-test utility and a full featured test panel.
Traditional NI-DAQ will have also have a test panel, but no self-test option.

Either way, the best place to start is with MAX.  All the previous steps apply to this card as well.  Most notably, using a (psuedo)differential input configuration for noise rejection.