Xiang Li

1. How do I use SCPI to add a label to channels? say &quot;PWM&quot; to chan1 and &quot;SW&quot; to ch2?&#160;<br> 2. How do I use SCPI to limit a chan (say ch2) to BW of say 20 MHz?

my question is are these below cmds correct?&#160;<br> if not, what should they be?&#160;<br> <br> <br> MEASUrement:MEAS1:SOUrce1 CH4D_0<br> MEASUrement:MEAS1:SOUrce2 CH4D_1

Hi,&#160;<br> I want to use SCPI to measure phase delay from D0 to D1 of ch4. I have TLP058 logic probes plugged into ch4.&#160;<br> I have tried the below SCPI cmds but they aren't working so I'm guessing I'm missing a space here/there?<br> <br> MEASUrement:MEAS1:type phase<br> MEASUrement:MEAS1:SOUrce1 CH4D_0<br> MEASUrement:MEAS1:SOUrce2 CH4D_1

Looks like I do have SVID sub but I'm not sure of the difference between the installed and upgrade one.&#160;<br> Please see pic attached.

Where can I purchase the license of protocol analysis for my MSO44 4-BW-500?&#160;<br> How do I know if it already has it?

Sometimes I get stuck on 

"*OPC?"

Sometimes I get stuck on 

read_raw(1920 * 1080)

Sometimes I get stuck on 

"*IDN?"

pyvisa.errors.VisaIOError: VI_ERROR_TMO (-1073807339): Timeout expired before operation completed.





 

I tried adding CLS in the init but I'm still having issues. 

def __init__(self, addr):
    self.addr = addr
    self.rm = pyvisa.ResourceManager()        # rm.list_resources()
    self.inst = self.rm.open_resource(self.addr)
    self.write("*CLS")
    print(self.query("*IDN?"))
    self.write("*CLS")

Do you see anything wrong with the below function? (I keep getting timeout errors at random lines in the below funciton. )
If not, can you please share a scope shot retrieving routine that's robust? 

def get_screenshot(self):
    now = str(datetime.datetime.now()).replace(":", "-")
    # print(now)
    self.write(f'SAVE:IMAGe \"C:/{now}.png\"')
    self.query("*OPC?")
    self.write(f'FILESystem:READFile \"C:/{now}.png\"')
    imgData = self.inst.read_raw(1920 * 1080)
    cwd = os.getcwd()
    full_path = cwd + "\\scope screenshots"

    Path(full_path).mkdir(exist_ok=True)

    filepath = full_path + "\\" + now + ".jpg"
    file = open(filepath, "wb")
    file.write(imgData)
    file.close()
    self.write(f'FILESystem:DELEte \"C:/{now}.png\"')
    return filepath

How is the accuracy of digital channels compared to analog channels. I know it throws out quite a bit of information. It's more like a threshold lo/hi. Do you think using this method is detailed enough if I'm interested in phase delay down to 0.1 degree? 

I'm analog channel limited. Would I be able to use the digital channels to measure phase delay among different clock signals? In a way that I'll be able to add a stat badge, limit the population and query the mean of those phase delays? See attached. 

It's almost impossible to get integer number of cycles on the scope so how do you collect duty cycle stat on the badge? Do you throw out the partial cycles on the left/right most and only collect from the full cycles? 

For the attached screenshot: would it be collecting stats from those 5 pulses?