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CRY (Cryo-payload EX)
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takahiro.miyamoto - 20:53, Friday 17 August 2018 (5834)Get code to link to this report
X-end 2F lack for ETMX suspension work
When the payload is excited by the coil-magnet actuator, we can see the harmonic noise at the photo sensor signal.
we are thinking these reason,
- come from cable in the chamber, since these cable do not have shield
- come from around electrical circuit
So I investigated around the digital rack.
At first, I tried to measure the transfer function of the Satellite box at X-end, however today I could not do due to a lack of preparation...
therefore I measured the power spectrum of the all photosensor at some situation.
 1. the one cable for the sensor-actuator detouched from the satellite box, and I excited (0.5Hz, 10000count, using "awggui") this detouched  actuator channel. (Fig.1)
     According to Fig.1, we can see the harmonic noise.
 2. I detouced the cable between coildriver and satellite box, and I excited same channel. (Fig.2) 
    However we can see the harmonic noise...
 3. finaly I turned off the coil driver. as this result, harmonic was vanished. (Fig.3)
(according to this figure, we can see some peak. this is the resonance frequency of the payload. My failure)
I didn't understand about this wraparound signal at this investigation.
I didn't understand about this wraparound signal at this investigation.When the payload is excited by the coil-magnet actuator, we can seeWhen the payload is excited by the coil-magnet actuator, we can see the harmonic noise at the photo sensor signal.
we are thinking these reason,
- come from cable in the chamber, since these cable do not have shield
- come from around electrical circuit
So I investigated around the digital rack.
 
at first, I tried to measure the transfer function of the Satellite box at X-end, however today I could not do due to a lack of preparation...
therefore I measured the power spectrum of the all photosensor at some situation.
1. the one cable for the sensor-actuator detouched from the satellite box, and I excited (0.5Hz, 10000count, using "awggui") this detouched  actuator channel. (Fig.1)
According to Fig.1, we can see the harmonic noise.
 
2. I detouced the cable between coildriver and satellite box, and I excited same channel. (Fig.2) 
However we can see the harmonic noise...
 
3. finaly I turned off the coil driver. as this result, harmonic was vanished. (Fig.3)
 
I didn't understand about this wraparound signal at this investigation.When the payload is excited by the coil-magnet actuator, we can see the harmonic noise at the photo sensor signal.
we are thinking these reason,
- come from cable in the chamber, since these cable do not have shield
- come from around electrical circuit
So I investigated around the digital rack.
 
at first, I tried to measure the transfer function of the Satellite box at X-end, however today I could not do due to a lack of preparation...
therefore I measured the power spectrum of the all photosensor at some situation.
1. the one cable for the sensor-actuator detouched from the satellite box, and I excited (0.5Hz, 10000count, using "awggui") this detouched  actuator channel. (Fig.1)
According to Fig.1, we can see the harmonic noise.
 
2. I detouced the cable between coildriver and satellite box, and I excited same channel. (Fig.2) 
However we can see the harmonic noise...
 
3. finaly I turned off the coil driver. as this result, harmonic was vanished. (Fig.3)
 
I didn't understand about this wraparound signal at this investigation.the harmonic noise at the photo sensor signal.
we are thinking these reason,
- come from cable in the chamber, since these cable do not have shield
- come from around electrical circuit
So I investigated around the digital rack.
 
at first, I tried to measure the transfer function of the Satellite box at X-end, however today I could not do due to a lack of preparation...
therefore I measured the power spectrum of the all photosensor at some situation.
1. the one cable for the sensor-actuator detouched from the satellite box, and I excited (0.5Hz, 10000count, using "awggui") this detouched  actuator channel. (Fig.1)
According to Fig.1, we can see the harmonic noise.
 
2. I detouced the cable between coildriver and satellite box, and I excited same channel. (Fig.2) 
However we can see the harmonic noise...
 
3. finaly I turned off the coil driver. as this result, harmonic was vanished. (Fig.3)
 
I didn't understand about this wraparound signal at this investigation.When the payload is excited by the coil-magnet actuator, we can see the harmonic noise at the photo sensor signal.
we are thinking these reason,
- come from cable in the chamber, since these cable do not have shield
- come from around electrical circuit
So I investigated around the digital rack.
 
at first, I tried to measure the transfer function of the Satellite box at X-end, however today I could not do due to a lack of preparation...
therefore I measured the power spectrum of the all photosensor at some situation.
1. the one cable for the sensor-actuator detouched from the satellite box, and I excited (0.5Hz, 10000count, using "awggui") this detouched  actuator channel. (Fig.1)
According to Fig.1, we can see the harmonic noise.
 
2. I detouced the cable between coildriver and satellite box, and I excited same channel. (Fig.2) 
However we can see the harmonic noise...
 
3. finaly I turned off the coil driver. as this result, harmonic was vanished. (Fig.3)
 
I didn't understand about this wraparound signal at this investigation.
Images attached to this report
5834_20180817134918_imv3excv3detouch.png 5834_20180817134925_imh123v3satelliteboxdetouchedfromcoildriver.png 5834_20180817134932_42.png
Comments related to this report
yutaro.enomoto - 16:33, Tuesday 28 August 2018 (5916)

Ushiba, Enomoto
To investigate this issue, we made a similar measurement of ITMX payload.
To conclude, we didn't see similar crosstalks reported here.

We investigated this way:
-- took reference spectra with no signals sent to coils
-- sent 0.5Hz/5000cnts singal to MN_H1, and looked at the spectra.
-- disconnected each point in the actuator signal line, between DAC (AI) and the output of the satellite box, and look at the specta for each case.
We put an example spectra.

Next things to do:
Investigate this issue at EX more deeply