SDS1104X-E using PyVisa. Can I get more sigfigs/precision?

• SDS1104X-E using PyVisa. Can I get more sigfigs/precision?
  Posted by SDMiller on 06 Jun, 2023 21:10
• My goal is to make a string of automated measurements to calibrate the amplitude of a sine wave against the output of an RMS circuit. I can get it all talking and I get my measurements. On the scope I see the measurement as 20.0221kHz, but VISA reports 'C1:PAVA FREQ', '2.00E+05.'
  
  Question: Is there a way to get the full 4 digits of precision that I see on the scope out of pyVISA?  I can deal with the format but with it rounding off like that it's making my test look better than it is.
  
  
• #1 Reply
  Posted by alm on 06 Jun, 2023 21:26
• This has nothing to do with PyVisa: PyVisa is just relaying what the scope sent back. You'll need to read the scope manual and see if the output format for measurements is configurable, or otherwise complain to Siglent.
• #2 Reply
  Posted by SDMiller on 06 Jun, 2023 23:13
• I've read the manual from Siglent. I don't see anything that looks like a measurement configuration but thought perhaps I was overlooking it. That was really my question, does anyone know if it can be done and if so how? It's not obvious from the manual but I'm not a VISA or Siglent expert.
• #3 Reply
  Posted by abeyer on 07 Jun, 2023 00:34
• Tried this?:

  Code: [Select]

  :FORM:DATA CUST,6
• #4 Reply
  Posted by SDMiller on 07 Jun, 2023 00:51
• I hadn't, thanks for the suggestion. Tried it on my scope via Siglent's EasyScope and it accepts it as a command with no error but unfortunately the output is still rounded to the 3 digits. I also tried reading back the one of  the custom params just in case it stored it there but no luck. Attached just in case I'm doing something wrong I can't see.
  
  
   >>>:FORM:DATA CUST,6
  >>>C1:PAVA? Freq
  C1:PAVA FREQ,2.16E+05Hz
  >>>C1:PAVA? CUST, 6
  >>>C1:PAVA? 6
  >>>C1:PAVA? CUST6
  
• #5 Reply
  Posted by noisyee on 07 Jun, 2023 06:51
• What FW version do you use?
  I tried mine SDS1204X-E with latest V6.1.37R10, it works fine.
  

  Code: [Select]

  >>>FORM:DATA CUSTom,3
>>>C1:PAVA? FREQ
C1:PAVA FREQ,1.00E+03Hz
>>>FORM:DATA CUSTom,7
>>>C1:PAVA? FREQ
C1:PAVA FREQ,1.000000E+03Hz
Wait a second...
  Okay, I got it. It's a bug
  

  Code: [Select]

  >>>FORM:DATA CUST,3
>>>C1:PAVA? FREQ
C1:PAVA FREQ,1.000000E+03Hz
>>>FORM:DATA CUST,5
>>>C1:PAVA? FREQ
C1:PAVA FREQ,1.000000E+03Hz
The short form of CUSTom doesn't work
  

  Code: [Select]

  >>>FORM:DATA CUSTom,6
>>>:FORMat:DATA?
FORM:DATA CUSTOM,6
>>>FORM:DATA CUST,3
>>>:FORMat:DATA?
FORM:DATA CUSTOM,6

• #6 Reply
  Posted by SDMiller on 07 Jun, 2023 15:40
• Thanks a ton for sticking with this. It was a combination of the CUSTom and that I was running older FW. Upgraded to 1.37R10 and now I'm seeing exactly what you're seeing. That's what I needed!
  
  >>>:FORMat:DATA?
  FORM:DATA CUSTOM,7
  >>>C1:PAVA? FREQ
  C1:PAVA FREQ,3.003000E+04Hz
  >>>FORM:DATA CUSTom,6
  >>>:FORMat:DATA?
  FORM:DATA CUSTOM,6
  >>>C1:PAVA? FREQ
  C1:PAVA FREQ,3.00300E+04Hz
  
  Simon
• #7 Reply
  Posted by 807 on 08 Jun, 2023 14:13
• Quote from: SDMiller on 06 Jun, 2023 21:10

  My goal is to make a string of automated measurements to calibrate the amplitude of a sine wave against the output of an RMS circuit. I can get it all talking and I get my measurements. On the scope I see the measurement as 20.0221kHz, but VISA reports 'C1:PAVA FREQ', '2.00E+05.'...
  

  
  Doesn't 2.00E+05 represent 200kHz, or am I having a brain fart in my old age?