M. E. Bräuer The Control System for the X-FEL Undulators Martin E. Bräuer, DESY Hamburg, HASYLAB Outline: Requirements and Concept Components Our Prototype Measurements Summary

M. E. Bräuer The Control System for the X-FEL Undulators Requirements and Concept synchronized gap movements comprise the modular setup => cells high reliability allow complex movement-schemes movements with high dynamics long-term availability of components Cell Segment: 4 synchronized motors gap: ≤ 1µm precision single-motor operation (“taper”) speed: (0, )mm/s force: ≤ 160kN Segment cell i-1cell i Intersection Intersection: ≤ 5 control variables (i.e.: position, current..) value: f(gap) synchronized: ≤ 10 µm gap cycle-time: ≤ 5 ms

M. E. Bräuer The Control System for the X-FEL Undulators.. complex movements Various “patterns”  need maximum flexibility ! Taper-mode: Diagnostics: Have ≥1 device switched-on at a time => Move quickly (>30 devices in an undulator!)

M. E. Bräuer The Control System for the X-FEL Undulators Industrial Controls: robust productivity fast markets (10y = an age !) cheap a huge market: O(200) German companies & safe Secure investments: Truly open standards (CANopen, SERCOS, RS232, EtherCAT) Vendor independent Multi-Vendor environments Industrial components

M. E. Bräuer The Control System for the X-FEL Undulators Motors Stepper Rotating magnets Static coils 1/1 step 1/2 step 1/4 step 1/8 step 1/16 step 1/32 step 1/64 step Stepper:Assume a rotor following encoder currentvelocityposition Servo-controller encoder ?? ? fieldbus Servo: Measure the rotor angle Synchron-Servo-Motor: 1kW ! 1€ From the automation market W Cheap, robust, well understood

M. E. Bräuer The Control System for the X-FEL Undulators Encoder Systems Measure the linear position of each axis => The encoder determine the accuracy/resolution Open, incremental encoders => reference-switch/mark needed Optical reading of a ribbon 20µm period length => sin,cos 1Vpp Electronic “oversampling” (x4096) => linear “steps” Resolution: ok, precision? Operating them ‘close’ to a beam Singular point of precision Mounting? ULE (ZERODUR-like) mountings => compensate thermal deviations

M. E. Bräuer The Control System for the X-FEL Undulators Control-System … … cell i high resolution encoder motors (multiturn) rotational encoder local control CPU (general network) real-time network coils motors (i.e. stepper) I/O signals (fieldbus-devices in cell (opt.) Dezentral periphery prec. analog out (SERCOS drives for Intersection) motor controller and amplifier Intersection Intersection not fully defined  need maximal flexibility

M. E. Bräuer The Control System for the X-FEL Undulators Safety issues Needed feature in industrial solutions Bus sensitive to many errors Robustness (no false alarms required (HERA!) Additional measures allways possible Axis synchronization has a high priority in commercial systems “It is all software” Yes, get this from professionals! We have to define procedures No problems found yet Commissioning phase “interesting” Have to foresee a indiv. Taper Several devices will be used in Petra III Interlocks Personal-safety Radiation safety To be defined later.. Total: 4x 132kW

M. E. Bräuer The Control System for the X-FEL Undulators The Protoype

M. E. Bräuer The Control System for the X-FEL Undulators Hardware Details Terminals: IO and Intersection 12mm CPU Controller / amplifier Power / safety 4x PWM output 4x 0..10v (0.01% prec.) 4x stepper (one mounted)

M. E. Bräuer The Control System for the X-FEL Undulators Measured Data: Precision Encoder vs. Motor 1 Rotor (incl. offset to get picture) 1 Axis and master (thin) 0.5µmt sample = 1ms Time [s] pos = gap/2 [mm]

M. E. Bräuer The Control System for the X-FEL Undulators Measured Data: Precision Encoder vs. Motor 2 Rotors (incl. offset to get picture) 4 Axis and master 50µm 150µm !  one bad spindle (known) Encoders & servo-loops: loose requirements on mechanics

M. E. Bräuer The Control System for the X-FEL Undulators First stress tests High precision – with 137mm ‘walk’ 0.5µm one axis all axis

M. E. Bräuer The Control System for the X-FEL Undulators First stress tests 17x open/close cycles with highest speed 0.5µm v: 272mm in 12.5s

M. E. Bräuer The Control System for the X-FEL Undulators Summary First electro-mechanical prototype working System got up successfully (HarWi / MTU still there) Found a good supplier Measurements ongoing No showstoppers found yet The control system can be used rather widely >10x faster than Profibus Based on ethernet Existing (support/interest by >170 companies) Open (fully documented) Have only 1 bus ! > 50µs tasks with I/O, dig. IO in 350µs, 100 Servos-Axis in 100µs Outlook New fieldbus: EtherCAT: