##// END OF EJS Templates
HG_REPOSITORIES » LPP » INSTRUMENTATION » USERS » JEANDET » SOLO_LFR_Notebooks
RSS
Added thermal tests with ADC clock modifications....
Added thermal tests with ADC clock modifications. Signed-off-by: Alexis Jeandet <alexis.jeandet@member.fsf.org>
jeandet - - Load All Authors

File last commit:

r7:8dac1f4f80b9
r11:ea8683773e38
Show More
LFR_CPU_POWERDOWN_EFFECT.ipynb
450 lines | 2.1 MiB | text/plain | TextLexer
/ LFR_CPU_POWERDOWN_EFFECT / LFR_CPU_POWERDOWN_EFFECT.ipynb
History | Annotation | Raw |Copy content |Copy permalink

LFR CPU Powerdown effect on power supply emissions

Observed Problem

During MEB EMC test tests a 96Hz plus its harmonics was found. This polution has been tracked down to LFR. After some investigations this has been correlated to the LFR Spactral Matrices computation module which produce an interuption after each SM.

At F0(24576Hz) LFR compute a FFT of 256 points each $\frac{256}{24576}=10.416667ms \Leftrightarrow 96Hz$

Since LFR CPU and Flight SoftWare uses powerdown feature, the CPU is sleeping most of the time and woken up at 96Hz by SM module which produces a peak in power consuption.

Test goal

The aim of this test is to validate if a software solution can reduce or remove this pertubation. In this test, the solution tested is to create a new task with the lowest priority to keep CPU busy and avoid entering powerdown mode.

setup

Instrument list

  • SPW brick: StarDundee USB SPW brick MK1
  • LFR PSU: Custom power supply
  • LFR EGSE: Custom waveform generator
  • I probe: Tektronix AM503A + A6302
  • USB Scope: DreamSourceLab DSLogic Oscillosocpe
  • LFR EQM2

Modified LFR FSW

Test Procedure

  1. Connect all equipment as described in setup
  2. Take pictures of the setup
  3. Calibrate I probes
  4. Start LFR EGSE
  5. Power ON LFR /
  6. check power consumption
  7. Boot LFR with FSW 3.2.0.15
  8. Record current and save it as FSW_3.2.0.15_STANDBY.csv
  9. Enter Normal mode
  10. Record current and save it as FSW_3.2.0.15_NORMAL.csv
  11. Enter BURST mode
  12. Record current and save it as FSW_3.2.0.15_BURST.csv
  13. Enter SBM1 mode
  14. Record current and save it as FSW_3.2.0.15_SBM1.csv
  15. Enter SBM2 mode
  16. Record current and save it as FSW_3.2.0.15_SBM2.csv
  17. Boot LFR with FSW 3.2.0.15 modified
  18. Record current and save it as FSW_3.2.0.15_NO_PWD_STANDBY.csv
  19. Enter Normal mode
  20. Record current and save it as FSW_3.2.0.15_NO_PWD_NORMAL.csv
  21. Enter BURST mode
  22. Record current and save it as FSW_3.2.0.15_NO_PWD_BURST.csv
  23. Enter SBM1 mode
  24. Record current and save it as FSW_3.2.0.15_NO_PWD_SBM1.csv
  25. Enter SBM2 mode
  26. Record current and save it as FSW_3.2.0.15_NO_PWD_SBM2.csv
  27. Turn OFF LFR
In [1]:
%matplotlib inline
import sys
import matplotlib.pyplot as plt
import numpy as np
import pandas as pds
from glob import glob
from IPython.display import display
from dateutil import parser
from IPython.display import HTML,Markdown,Math
from IPython.display import display

HTML('''<script>
code_show=true; 
function code_toggle() {
 if (code_show){
 $('div.input').hide();
 } else {
 $('div.input').show();
 }
 code_show = !code_show
} 
$( document ).ready(code_toggle);
</script>
 <a href="javascript:code_toggle()"><font size="6">Show/Hide code</font></a>.''')
Out[1]:
Show/Hide code.
In [2]:
def plot(files,names,x_range=(1e1,5e2)):
    plt.figure(figsize=(28,14))
    for file,name in zip(files,names):
        data=pds.read_csv(file,comment=';',skiprows=5,decimal=',',sep='\t')[:1024*512].as_matrix().flatten()
        size=len(data)
        avg=np.mean(data)
        data-=avg
        spec=np.fft.fftshift(np.abs(np.fft.fft(data*np.hanning(size)))/size)
        f=np.fft.fftshift(np.fft.fftfreq(size,1./5e5))
        plt.plot(f,spec,label=name)
    plt.xlim(*x_range)
    plt.ylim(1e-4,1.5)
    plt.legend()
    plt.semilogy()

Analysis, 3.2.0.15 Versus modified version comparaison between 10Hz and 500Hz for each mode

STANDBY mode

In [3]:
plot(["../DATA/FSW_3.2.0.15_STANDBY.csv.gz","../DATA/FSW_3.2.0.15_NO_PWD_STANDBY.csv.gz"],["Default","With_Scrubbing"])

NORMAL mode

In [4]:
plot(["../DATA/FSW_3.2.0.15_NORMAL.csv.gz","../DATA/FSW_3.2.0.15_NO_PWD_NORMAL.csv.gz"],["Default","With_Scrubbing"])

BURST mode

In [5]:
plot(["../DATA/FSW_3.2.0.15_BURST.csv.gz","../DATA/FSW_3.2.0.15_NO_PWD_BURST.csv.gz"],["Default","With_Scrubbing"])

SBM1 mode

In [6]:
plot(["../DATA/FSW_3.2.0.15_SBM1.csv.gz","../DATA/FSW_3.2.0.15_NO_PWD_SBM1.csv.gz"],["Default","With_Scrubbing"])

SBM2 mode

In [7]:
plot(["../DATA/FSW_3.2.0.15_SBM2.csv.gz","../DATA/FSW_3.2.0.15_NO_PWD_SBM2.csv.gz"],["Default","With_Scrubbing"])

Modified FSW mode comparaison

In [8]:
modes=["STANDBY","NORMAL","BURST","SBM1","SBM2"]
files=["../DATA/FSW_3.2.0.15_NO_PWD_{mode}.csv.gz".format(mode=mode) for mode in modes]
plot(files,modes,x_range=(5e1,1.5e2))

Default FSW mode comparaison

In [9]:
modes=["STANDBY","NORMAL","BURST","SBM1","SBM2"]
files=["../DATA/FSW_3.2.0.15_{mode}.csv.gz".format(mode=mode) for mode in modes]
plot(files,modes,x_range=(5e1,1.5e2))

Conclusion

It is possible to reduce 96Hz emmision from LFR with a software modification, while this doesn't remove totaly the 96Hz pike this might be enough. It might also be possible to improve this result with more software modifications.