Initial unwanted pulse on AnalogOutConfigure

[spri]

I am writing a custom GUI to send and monitor pulses.  One system sends a constant background pulse (black) to one piece of hardware, meanwhile the user specify inputs for the pulses for the other systems. When a button is pressed, the configurations are set up and the device is set to wait for a trigger to begin generating the analog pulses.  However, I get a single first pulse from the analog waveform generators (blue&red) when the configuration button is clicked, before the  PC trigger line pulse is sent. How do I eliminate these initial configuration pulses? 

 

This is the code for the configuration. When this method is called I get the single analog pulse outputs.  Everything works properly after that  ie- the analog pulses start on the correct trigger signal.

    
    def ArmTrigger(self):

            # analog pulse control setup
            self.dwf.FDwfAnalogOutNodeEnableSet(hdwf, c_int(0), AnalogOutNodeCarrier, c_int(True))
            self.dwf.FDwfAnalogOutNodeEnableSet(hdwf, c_int(1), AnalogOutNodeCarrier, c_int(True))
            self.dwf.FDwfAnalogOutMasterSet(hdwf, c_int(1), c_int(0)); # for second channel set master the first channel, slave channel is controlled by the master
            self.dwf.FDwfAnalogOutNodeFunctionSet(hdwf, c_int(-1), AnalogOutNodeCarrier, funcSquare)
            self.dwf.FDwfAnalogOutNodeFrequencySet(hdwf, c_int(-1), AnalogOutNodeCarrier, c_double(self.xRate))
            self.dwf.FDwfAnalogOutNodeAmplitudeSet(hdwf, c_int(-1), AnalogOutNodeCarrier, c_double(1)) 
            self.dwf.FDwfAnalogOutOffsetSet(hdwf, c_int(-1), c_double(0))
            self.dwf.FDwfAnalogOutNodeSymmetrySet(hdwf, c_int(-1), AnalogOutNodeCarrier, c_double(symm)) #pulse width
            self.dwf.FDwfAnalogOutNodePhaseSet(hdwf, c_int(1), AnalogOutNodeCarrier, c_double(self.x2Phase)) #phase shift for second channel
            self.dwf.FDwfAnalogOutRunSet(hdwf, c_int(-1), c_double(self.xDuration))  #set run duration on all channels
            self.dwf.FDwfAnalogOutIdleSet(hdwf,c_int(-1), c_int(0))

            #set up PC trigger to start pulse output AND acquisition
            self.dwf.FDwfAnalogOutTriggerSourceSet(hdwf, c_int(0), trigsrcPC)
            self.dwf.FDwfAnalogOutTriggerSlopeSet(hdwf, c_int(0), c_int(0)) # set master channel to trigger on rising edge

           #configure everything to wait for trigger
            self.dwf.FDwfAnalogOutConfigure(hdwf, c_int(0), c_bool(True)) # start master, slave will follow 

                 
            self.StartButton.setEnabled(True)  #start button click sends trigger line pulse with dwf.FDwfDeviceTriggerPC(hdwf)

 

 

[attila]

Hi @spri

The unwanted pulse is caused by the configuration order. The default idle output is the initial value and when first you configure funcSquare it outputs this until the idle output is changed.
Move the idle before function setting:
...
dwf.FDwfAnalogOutIdleSet(hdwf,c_int(-1), c_int(0))
dwf.FDwfAnalogOutNodeFunctionSet(hdwf, c_int(-1), AnalogOutNodeCarrier, funcSquare)
....

[spri]

Thank you, that worked perfectly!