LHC BWS CONS meeting #8 | 02.05.2023
https://indico.cern.ch/event/1270379/
First scans with the hybrid prototype and LIU-based electronics on LHC Beam 1
(J. Emery)
- The hybrid mechanism with LIU electronics operates at 0.92 m/s.
- Software is also from LIU, all the FESA layers are working and were used for the tests.
- 3 IN-OUT scans are usable.
- The acquisition provided the optimal channel (CH2) with 400V volt on the PMT.
- Systematic position offset between IN and OUT, most probably due to resolver processing.
- Beam size is slightly smaller on the IN scan compared to the OUT.
- Python fit and front-end fit don’t always give the same sigma, to be investigated.
- More statistics to come possible during BSRT calibration.
- MD is foreseen between the 14 and 18 June. Presentation: https://indico.cern.ch/event/1278851/
Magnetically coupled actuator scan analysis and system modelling
(V. Varadan)
- Laboratory tests of the UHV BAT push-pull system.
- The system not under vacuum, with linear encoders at the air side and at the vacuum side to study the coupling.
- System tested with DSpace controller at various speeds (0.1, 0.2, 0.5, 0.75) m/s.
- For each speed, the positions curves and Bode plot [FFT(vacuum side)/FFT(air side)] is shown. => The start and end positions of the vacuum side vary. When the magnetic circuit between the air and vacuum side are aligned, there is ~0 force, so the vacuum side stops before or after due to friction.
- The system works at 1 m/s (video), but the vacuum side encoder gives an error.
=> Suggestion to fix the bench directly on the table without the rubber feet to stabilize - Reproducibility of the system displacement at 0.75 m/s at the interaction region is higher (212.6um) compared to results received from NPL laboratory (40um).
- Two identifications of the coupling using ARX (Auto Regressive model with external inputs) are presented. One using the whole data set of motion at different speeds and one using PRBS (pseudorandom binary sequence).
- The second data set gives the best results and can reproduce the oscillation seen at the end of the movement with the same phase but lower amplitude.
- Next: fix 1m/s data taking issue, run reproducibility and identification, and design trajectories to ensure reproducibility.
LHC wire scanner mechanical brainstorming status
(R. Veness)
- Designs definition, all to be compatible with the LIU control system.
- Hybrid -> the ones installed in B1H2 & B2H2: Same vacuum side as the legacy system, but with new motor & ball-screw without springs to compensate the vacuum force.
- Hybrid+ -> Hybrid mechanism, compatibility with existing tank + re-designed vacuum parts: forks assembly and electrical feedthrough, magnetically coupled drive depending on the ongoing development.
- Full consolidation -> new mechanism and new tank, suggestion to use 45 deg. to ease the integration into the LHC. Design solutions still to be decided: Drive coupling (bellow/magnetic/linear motor), forks assembly and feedthrough, position encoder.
- The full consolidation strategy includes linear motor bench, tank for SPS/LHC in YETS23-4 or just on calibration bench, and position sensor.
=> info:
linear motor bench conceptual design: https://edms.cern.ch/document/2868812/1
linear position sensor integration concept: https://edms.cern.ch/document/2670995/1
Discussion & other status (all)
LINMOT compatibility with the LIU BWS electronics
(4 Slides, J. Emery)
- A quick check of the LINMOT compatibility with the LIU electronics.
- They have a line of products compatible with ‘standard’ drives from other manufacturers.
- Part Number check: PS10-70X80U-BL-QJ-D01 -> 561N peak force
- Max current, not an issue (11 A) to check current ctrl at low values <1A.
- Back EMF constant 58.9V -> ~OK at 1m/s but NOT OK at 3m/s (180V lost!)
- Magnetic period: 40mm at 1m/s mean 25 Hz fundamental => OK
- The bigger problem is the integrated encoder that is incompatible with radiation (it embeds electronics).
- Encoder signals are not compatible with LIU electronics. We need the equivalent of the resolver (variable transformer) for linear motion.
- Does the company willing to work with us on a compatible version?
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