VERTEX ANTENNENTECHNIK Gmb H Arecibo Telescope Servo Drive

VERTEX ANTENNENTECHNIK Gmb. H Arecibo Telescope Servo Drive System Ideas For Computer Upgrade Arecibo Telescope Servo & Drive System -1 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Arecibo Telescope Servo & Drive System -2 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Computer Upgrade Concept I u (Existing) PLC u Ø hardware can be re-used to a large extent Ø hardware (except CP 581) is still will be available for many years Ø CP 581 will be removed Ø PLC function will be limited to safety functions and low level operation Ø interface to servo computer via serial interface (new card) – not time critical! Arecibo Telescope Servo & Drive System New Servo Computer Ø Local User Interface (replaces existing LCU) Ø tasks: • • encoder readout operating mode control M&C Interface to host position loops Ø output to DCS: analog velocity commands -3 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Computer Upgrade Concept II u Drive Control Ø Ø u Ø presently read by PLC Ø new (possibility 1) motors to be re-used servo amplifiers to be re-used complete DCS to be re-used additional setpoint from servo computer: • • • DCS boards can handle additional setpoint analog signal must be wired from backplane SUB-D connector to board connector PLC software must control selection relay Arecibo Telescope Servo & Drive System Encoders only computer reads encoders position dependent PLC interlocks cannot be kept Ø or (possibility 2) • • • -4 - install SSI doublers both computer and PLC read encoders position dependent PLC interlocks can be kept Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Computer Upgrade Concept III u OCU in main control room u Ø also to be replaced Ø new OCU could be … • • • Interface to host computer Ø remains on Ethernet Ø protocol a desktop PC with keyboard and mouse, running on Windows a rack mounted touch screen panel PC a notebook PC • • • … could be kept … or extended/modified according to present experience … or completely changed Ø logs into servo computer via Ethernet Ø existing serial link no more required Arecibo Telescope Servo & Drive System -5 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Arecibo Telescope Servo & Drive System -6 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Possibilities for Servo Computer u PC u J in-expensive J easy replacement / upgrade K interface boards to encoders etc. to be found K existing application software to be adapted to hardware and software platform L reliability for operation unknown L becomes obsolete very fast L spare part availability Arecibo Telescope Servo & Drive System Industrial Servo Computer J proven reliability J all interface hardware available J interface modules comply to more stringent specifications J spare part availability J application software available to a large extent J prepared for future upgrades L more expensive than PC L software and drivers written for a particular hardware configuration -7 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Vertex Antenna Control Unit 8100 u u Vertex Antennentechnik’s standard controller for high accuracy antennas and telescopes since 2001 Installed at Ø ESA 35 m Deep Space Antenna (servo accuracy ~2 mdeg) • • Ø Ø Ø Ø u Australia: in operation Spain: presently being built various (fast) ESA 15 m antennas (~20 mdeg) ALMA Radio Telescope (~0. 15 mdeg) APEX Radio Telescope (~0. 15 mdeg) AMIBA Hexapod Telescope (~3 mdeg) CNR 32 m Radio Telescopes at Noto and Medicina (~1 mdeg) Eumetsat Polar Station, Svalbard (~20 mdeg) various other stations Several more installations in progress Arecibo Telescope Servo & Drive System -8 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Arecibo Telescope Servo & Drive System -9 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Arecibo Telescope Servo & Drive System - 10 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Vertex Antenna Control Unit 8100 u Concept: u Ø Compact. PCI bus Ø Vx. Works 5. 5 RTOS Ø P III 1. 3 GHz CPU with 2 Ethernet interfaces Ø 10. 4” Color Touch Screen as local user interface (separate PC running on Embedded XP) Ø multiple user interfaces feasible Ø several types of interfaces to host / encoders / drive cabinet available Arecibo Telescope Servo & Drive System Tasks: Ø drive control • • fully digital Az/El drive control or position loop only with analog velocity command output Ø Ø Ø position readout from encoders operating modes interlocks on software level local control of all functions pointing error correction (option) communication to interlock system PLC Ø Interfaces to host computer - 11 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Arecibo Telescope Servo & Drive System - 12 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Vertex Antenna Control Unit 8100 6 HU-Version of ACU 8100 4 HU-Version of ACU 8100 Arecibo Telescope Servo & Drive System - 13 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H New Antenna Control Unit 8100 (6 HU) Arecibo Telescope Servo & Drive System - 14 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Sample Local User Interface Arecibo Telescope Servo & Drive System - 15 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Advantages of Suggested Approach u Limited scope of upgrade u Ø computer replacement only Ø “budget-friendly” solution u Ø PLC software • Re-Use of components • Ø drive cabinet, PLC and servo amplifiers Ø encoders Ø motors u Low risk Ø the working interlock system and low level control will be re-used Ø return to existing system can easily be achieved Ø use of well proven components Ø limited software effort Arecibo Telescope Servo & Drive System Limited software effort can be re-used to large extent various functions not used any more Ø Servo computer software • • u functionality already existing only adaptations required for Arecibo (interfaces, specific interlocks etc. ) Limited telescope downtime Ø Estimated total downtime approx. 2 -3 weeks Ø With a little more effort, it would even be possible to return to operation every night - 16 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Possibilities for Future Upgrades u Fully Digital Drive System J very flexible control loop structure J improved performance J much easier to be tuned than analog DCS J insensitive to EMI etc. J less components …less failures L … more software L measurement of commands to servo amplifiers is difficult and requires analyzers or test outputs in the computer (even more software…) Arecibo Telescope Servo & Drive System u u - 17 - Adaptation to new host computer(s) Extended operating modes Drive cabinet or servo amplifiers only Motors ? Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Arecibo Telescope Servo & Drive System - 18 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Fully Digital Drive System u u u u Position and velocity loops closed in servo computer Servo computer provides torque command to each motor via local bus In low level control the servo amplifiers receive analog commands Configuration of servo amplifiers is controlled by PLC via digital inputs to amplifiers Existing drive motors could be kept Servo amplifiers (or entire drive cabinet) needs to be replaced Analog DCS could Ø … be kept for low level control Ø … be removed, leading to a much simpler but “less comfortable” drive concept in low level control Arecibo Telescope Servo & Drive System - 19 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK Gmb. H Arecibo Telescope Servo & Drive System - 20 - Technical Meeting May 2004