how to acquire a analog data, manipulate and receive at o/p using DAQ(usb-6008)

[9990676224]

hi,

I am using DAQ (usb-6008) to acquire a analog data. I am to  receive this data after some manipulation (not specific, let devide dy 4).

then what programing i have to use to access data from DAQ i/p and to generate at DAQ o/p channel.

please make a fast repply...

thank's...  

[Dennis_Knutson]

What you do will depend on the type of data you want to recieve and send. If you do a single point acquisition with a DAQmx Read, then you can manipulate it and wire the result to a DAQmx Write. If it's a waveform that you receive, then you will have to put the DAQmx Write in a loop and send a single point of the waveform with each iteration of the loop. That is because the analog out of the USB-6008 is software timed and your only option for writing is on-demand, single point.

[9990676224]

 hi sir,

i am getting an error coded as (-200077) from DAQmx start task.vi, while i am running the program sent by you, with my DAQ (usb-6008).

please tell me what may be the reason for this error and how can it be eliminated.

[Dennis_Knutson]

Which program are you running, which Start Task is throwing the error, and how have you defined the channels? The second onw is just a simple copy of the first to show how the analog write could be done. You would want to add a DAQmx Timing function like the shipping examples show. I don't think that would cause that error though.

[BrowningG]

Hello 9990676224,

The programs that Dennis provided are great starting points for using both analog input and output in the same program. 

The error (-200077) that you are receiving when running these programs is due to the fact that a USB 600x device has an analog output range of 0 to 5 V.  These values can be found in the specifications sheet for the USB 600x, or from the error that is thrown when the task starts.  I have included a screenshot of the error text. 

When the analog output task is configured, the default range is used if nothing is wired to the minimum and maximum value inputs.  The default values for these inputs are -10 and 10 V respectively.  By wiring a constant or control to these inputs, you can change these values. 

This forum post shows another way using dataflow programming to update the output value based on the read value. 

Getting Started with NI-DAQmx and Learn 10 Functions in NI-DAQmx and Handle 80 Percent of Your Data Acquisition Applications are great starting points for programming with DAQmx. 

Message Edited by BrowningG on 10-29-2007 06:13 PM