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Negative bias voltage limit cannot be changed

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2024-05-22
2024-05-28
  • Yoichi Miyahara

    Yoichi Miyahara - 2024-05-22

    Hello all,

    I am using a custom external voltage amplifier to apply the bias voltage higher than +-10V.
    I changed 'Instrument/Bias-Gain' in the preference to the gain of the amplifier (x3).
    While I could change 'Upper Limit' of dsp-fbs-bias to 30V, I could not change 'Lower Limit' for some reason.
    Whenever I put a new value lower than -10V, it does not allow.

    Is there any other way to change this limit?

    Thank you,
    Yoichi

     
  • Percy Zahl

    Percy Zahl - 2024-05-23

    I have to check if there is (must be, just not sure it it is at -10V) limit for the "neg limit" setting if I understand you right.... hang on...

     
  • Percy Zahl

    Percy Zahl - 2024-05-23

    There is some odd issue, a more generic gxsm wide issue effecting all neg limits, been reset to -10 when edited...

    For a work around, do NOT use the dialog to adjust the limits, BUT use the system tool dconf Editor. See screenshot attached. Find the setting as shown and adjust the limits as desired (I put +/-20 in for a test).
    Do this before starting gxsm3 -- or restart it after adjusting as it does not get a change notification if you edit it there!

     
  • Yoichi Miyahara

    Yoichi Miyahara - 2024-05-24

    Thank you, Percy. The method with dconf-editor works for dsp-fbs-bias.
    However, I noticed that it does not work for dsp-z-start. Even after I did the same kind of changes with dconf-editor, the negative limit value goes back to 10 V. Very strange.

     
    • Percy Zahl

      Percy Zahl - 2024-05-24

      Send me what all "unusal limits" need and I'll have a look.

       
  • Yoichi Miyahara

    Yoichi Miyahara - 2024-05-28

    I tried to change dsp-z-start by dconf-editor once again, it works now. Sorry for confusion.

     
    • Percy Zahl

      Percy Zahl - 2024-05-28

      OK.

      BTW: You actually can reconfigure the limits (lower included) via Gxsm I found:
      Open the configure Dialog and type in the value you want, BUT do not hit Enter or do anything else, just click OK and it takes it!

      PS: I have not yet figured out why it complains for all limits at -10 when hitting enter, or do anything else... and set it back to -10 then.

      PPS:: Fixed the config dialog issue. In git now. The Entry Spinner-Limits/updates were interfering, removed spin feature from config as not needed here solved the issue.

       

      Last edit: Percy Zahl 2024-05-28
  • Yoichi Miyahara

    Yoichi Miyahara - 2024-05-28

    I tried the way you described. It indeed works!
    Thank you!

     

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