Hi vkhatri,
I don't know the device that you are using, so I'll assume that it is one of our M Series or E Series DAQ devices. If this is the case, only one analog input task can be running at a given time because all of the AI channels use the same multiplexer and timing engine. You can include multiple channels in the same analog input task by just modifying the syntax of the "Physical Channels" input of the DAQmx Create Channel.vi.
For example, an input of "Dev1/ai0:4" would set up the task for channels 0 through 4, and an input of "Dev1/ai0, Dev1/ai3:6" would set up the task for channels 0, 3, 4, 5, and 6. More information about the syntax for a list or range of channels can be found in the LabVIEW help. In addition, there is a useful resource on our website
here for information about programming in LabVIEW with NI-DAQmx.
Regards,
Andrew W
National Instruments
