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Design, Manufacture, Transport and Integration on-site in Chile of ALMA Antennas ENCODERS

Design, Manufacture, Transport and Integration on-site in Chile of ALMA Antennas ENCODERS PM#07 13-14 September 2006. ENCODERS - Update Status. AZ encoder baseline: Heidenhain ERA780C : Reading heads possibly reduced to 8 instead of 10; decision at the final definition of bearing.

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Design, Manufacture, Transport and Integration on-site in Chile of ALMA Antennas ENCODERS

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  1. Design, Manufacture, Transport and Integration on-site in Chile of ALMA Antennas • ENCODERS • PM#07 13-14 September 2006

  2. ENCODERS - Update Status • AZ encoder baseline: Heidenhain ERA780C: Reading heads possibly reduced to 8 instead of 10; decision at the final definition of bearing. Several interactions performed between EIE/MTA and bearing supplier, in order to fix the final tolerances for encoder tape interface. Azimuth assembly drawing prepared for interfaces/assembly definitions. Dedicated procedures for tape installation/fixation/cutting, under definition and discussion. Specific analysis, for moisture possible presence inside the base/yoke volume, under development. • Heidenhain refused to perform any moisture/icing condition qualification test on the tape. • Alternative qualification program under evaluation. • Solution to mitigate this risk (protection around the tape, air drier inside the base, slight pressurization around the tape), under evaluation. • AZ encoder alternatives: BEI and SEIKI still as possible backup solution.

  3. ENCODERS – Moisture: Risk Analysis

  4. ENCODERS - Update Status • EL encoder baseline: Heidenhain ERA 4282C: 150mm internal diameter fixed as baseline solution. 120mm internal diameter solution: accuracy tests performed by the supplier. Overall cover: study prepared and submitted to the supplier for comments. This cover will be not part of encoder supplier delivery. Mounting and alignment w.r.t. the shaft issues still under AEM internal discussion and analyses. • Alternative Solutions: BEI and SEIKI still as possible backup solution.

  5. ENCODERS - Update Status • Interpolation Electronic baseline: Heidenhain IK320V: Product considered valid also for the ALMA production. Material available in supplier stock for 20 complete units. Long term delivery items (6 months) to be ordered w.r.t. the ALMA schedule; no criticality. The hardware configuration of the cables arriving from the heads on the ACU crate will change respect to the prototype; extra connections (passages within the crate) will be eliminated. No firmware update from the prototype.

  6. ENCODERS - Update Status • Interpolation Electronic Alternative: Heidenhain EIB741: Product returned as viable solution for ALMA and Heidenhain standard production just the 12.09.2006; verification of development time and porting issues under analysis. Hardware interface totally changed between AC and the board; anymore inside. By means of Ethernet and distributed electronics, it would be possible to reduce the cables passing trough the AZ cable wrap. The Compensation, from static (IK320V), will become dynamic (no compensation runs needed). The main proposed characteristics, are hereunder reported:

  7. ENCODERS - Update Status

  8. ENCODERS - Update Status

  9. Encoders Block Diagram with IK320V solution

  10. Design, Manufacture, Transport and Integration on-site in Chile of ALMA Antennas • ACU • PM#07 13-14 September 2006

  11. ACU - Update Status • ACU H/W baseline: • Under discussion and definition with the possible suppliers • Evaluation of supports for RTAI for the various H/W • Under evaluation the possible use of screened LCD monitor for the local control • ACU H/W alternative: • Definition of possible use or not of Openbrick, under evaluation. • Interface to new possible encoder interpolation boards, under discussion. • ACU S/W activities: • Definition of possible use or not of Openbrick, under evaluation. • Simulink model for Servo analysis under preparation, based on a reduced FEA model

  12. ACU - Update Status • ACU H/W possible solution: • n.1 RackPack/8A-20 19" VMEbus Chassis • n. 1MVME5500-0161 CPU module, 1GHz MPC7455, 512MB Motorola • n.2 TVME220-10 VME64x IP-Carrier, Backplane I/O TEWS • n.2 TVME001-TM-10 I/O Adapter for backplane I/O TEWS • n.1 TIP501-10 16 channel 16-bit ADC IndustryPack TEWS • n.2 TIP551-10 4-channel 16-bit DAC IndustryPack TEWS • n.1 IP675-10 48 TTL I/O IndustryPack tri-state I/O’s TEWS • n.1 TIP865-30 4 channel RS485 IndustryPack TEWS • n.1 TPMC816-10 2 channel extended CAN PMC TEWS • n.1 ADAM-6051 Ethernet Data Acquisition Module Advantech • ACU H/W alternative: • Interface to new possible encoder interpolation boards, under discussion. • Definition of possible use or not of Openbrick, under evaluation.

  13. Preliminary Crate Layout - Front

  14. Preliminary PCU Layout

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