Make sure that the active window is notthe one that contains the source waveform for the arbitrary waveform.
For example, you have two files: test and source. Source is the file that contains the arbitrary waveform and test is the file that you will use to send out the stimulation and possibly acquire data. Open up the stimulator setup window (MP150>Set Up Stimulator)when the test file is active. Only then will source be listed in the source graph box.
If you have multiple channels in the source file, only the selected channel will be used as the arbitrary waveform. Also, if you have selected a section of the data in the source file, only this section of data, on the selected channel, will be used as the arbitrary waveform for stimulation. Finally, make sure that the number of repeats is set to Once or Forever (not Off) in the stimulator setup window.
