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| * With the circuit, noise in the output from the photosensors are reduced to reach ADC noise level... '''''to be reported in detail''''' | * With the circuit, broad strange noise in the output from the photosensors are reduced to reach ADC noise level... '''''to be reported in detail''''' |
20180223
- [[]]
Today's activities
Workers: Simon, Miyo, Akutsu
- Reconnected the coil's pins to 4-ohm ones; from U/V to C/D in P23.
- After several trials, realized 20V 1A to the coil made the WAB moving.
The 1A was consistent with our experience at Mitaka in spite of the magnets had been Neodymium but now SmCo.
- The supplied current was able to be monitored at the display on the power supplies, but the current got reducing step by step... firstly I was surprised, but this could show the resistance was increasing; I observed the current got down to 750mA (I have no idea if this would have reach in equilibrium); Simon touched the coil with gloved his finger and felt warm.
- Well, don't keep the current turned on.
The power supplies are Matsusada Precision P4K-80L, which Akutsu brought two from Mitaka; they can output 16V max, so I connected them serially.
Attached 470nF parallelly to the transimpedances in the OSEM satellite box S1604897 that drives all the photosensors.
With the circuit, broad strange noise in the output from the photosensors are reduced to reach ADC noise level... to be reported in detail
- Measured the damping behavior by exciting the WAB suspension by the coil actuator, and observed by the photosensors (3DoF) and the oplev (2DoF)
To be reported
- (CAL people installed a TCam to see IYC, and now pictures of the WAB can be shot!)
[Ongoing] Need cares of water springs from anchor bolts for oplev pylons.
[Ongoing] Need to confirm what are the scratch lines made by the measurement by the KEK team last week.
Next plan
- Change the pin assign so that enough current can flow to the coil.
- Add capacitors to the transimpedances in the OSEM satellite box.
- Complete the calibration of the oplev; the arm length was reported by Simon, so....
- Check the balance of the suspended WAB with some wires and sensors are attached.
- Check how the damping would be now after the replacement of the damping magnets.
- Check the reproducibility of the alignment of the suspension among several modes.
- Check heights of several points.
- Take care of water spring??
Wanted!
- Two burndy connectors, vacuum compatible.
Stages outside the chamber to ease wiping our legs.
Good rail(?) to move the WAB suspension in the cryostat in the main beam direction.
Chain block? to support the load in the chamber.
- A clock to know the time easily.
- M6 screw set.