Activity for Wenxuan Qian
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Wenxuan Qian posted a comment on discussion Help
Hi Percy and Thorsten, Thank you for your kind suggestions, but it seems that I still have those noises in my set. I attached a picuture of my the result of ZS(6) measured by osciloscope , with feedback loop disabled. It seems the noise level is at about 5mV. Guess that is also not good. I also attached a pic from srx_analog810_selftest. It seems that we are having some red lights. But sorry I don't quite understand it... We are little worried about whether the card is having some problems or not....
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And here are the pic of of our set and signals shown by osiloscope.
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Dear Thorsten, Thanks a lot for your advice, I just shortened all the free input connector and relinked the ground loop to our STM system. But this low signal of about 50mV still remains. Probably also because of this, the feedback loop reads in the tunneling current varies from 0.5nA to 20nA while I set (CP=CI=5, Vbias= -1V, setpoint=1nA, for good sample). I am wondering that is there any chance that there is something wrong with our card? In that case probably I will have to contact the staff and...
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Dear Thorsten, Good day! I did some more test and I found by osiloscope that there was always a quite strong low frequency vibration signal come into view every few seconds at the FB1 for feedaback loop. Probably this is the cause of unstable feedback loop (Please see the attachment). I am wondering if you may also experienced that? Additionally, I found that the PanView is not working prefectly in my GxSM3. It always reads in a -0.4nA signal (I am using 0.1nA/V as the gain). It will vanish and leave...
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Dear Thorsten, Yes, I have also done that, but problem remains. I will reflash it again and see whether there is any change. I would be appreciate if you may come up with any other possible cause of this problem!
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Dear Thorsten, Thanks for the prompt reply! I am using the GXSM 3.53.0 and I just reflashed the board accordingly. (Sorry but is that what you mean?) Thanks a lot!
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Hi everyone! I am still working on our STM set with a MK2-A810, gxsm3 but I have countered some problems with my feedback loop. If anyone can give me some suggestions that would be great! The test sample I use is HOPG, the bias I set is -1V, setpoint was at 0.1A Cp=12, Ci=10 (The V/nA=0.1V/nA) Now I can reach the tunneling area without problem. But when the approach process is done, the tip seems to be vibrating, with the tunneling current varied from 1nA to 20 nA. I tried both positive and polariety...
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Hi Percy, Thanks for your answer! I use : gxsm.set ("dsp-fbs-bias",Voltage_set) to output voltage and use: fvec = gxsm.rtquery ("f") temp=1000*float(fevc[1]) * to read in the voltage. Now I am feeding it a 0.557V but the voltage it reads seems to show 582.25382053590 Thanks for the lighting up, going to check the configuration in GxSM. Qian
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Hi everyone! I just got a MK2-A810 from my colleague, but I found that there probably is something wrong with my hardware, I am wondering that whether you may have a clue about it? The bias voltage (VB(7)) is not outputing correcting value, e. g. it will give out 1.04V if I use python script to try to let it output 1.0V The ADC (FB-1) also seems a little bit strange, e. g. it reads in 0.340V if I feed it with an input of 0.370V I am wondering if there is anyway to calibrate it? Thank you all for...
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