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Published byCharleen Beasley Modified over 9 years ago
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Mar 18, 2003PFIS CDR1 Control System Summary of Changes Since PDR All the motors, drivers, sensors, switches, etc. have been chosen Built up a mechanism using typical parts, a slit mask elevator mockup Designed and built a client/server system in LabVIEW: uses all proposed LabVIEW functions: data sockets, queues, string parsing, analog input, closed loop motion control. Ran the mechanism at all three proposed levels of control: actuator, mechanism, and system level (with a slit mask searching procedure) Control System wiring has been completely designed. PFIS “Generic Mechanism” Used for proof-of-concept testing
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Mar 18, 2003PFIS CDR2 Control System Hardware Block Diagram Control fiber to payload AC & RS232 from payload back to top hex, for Etalon controllers 3 PFIS cooled electronics boxes inside PFIS structure Main (Chassis, power supplies) Box 1 (Slit mask, wave plate, shutter, focus) Box 2 (Beam splitter, Grating, Filter, Articulation)
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Mar 18, 2003PFIS CDR3 Control System Power Management and Distribution SALT Isolator switch provides power to all of PFIS Within PFIS, PXI & sensors can be powered without power to actuators Motors and pneumatics are each powered separately Etalon High Voltage is interlocked with sensors near HV connectors.
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Mar 18, 2003PFIS CDR4 Control System Status of Electrical Design All components have been identified and assigned locations: –Main box with PXI chassis, power supplies, digital & analog inputs –Satellite box 1: slit mask, wave plate, focus, and shutter –Satellite box 2: grating, filter, articulation, and beam splitter Wiring diagrams & interlock logic are complete - ready to buy & build Each satellite box implements its interlocks with a Programmable Logic Device –All end-of-travel conditions are sensed –We use a “fail asserted” approach: a broken wire looks like a hard limit –Each hardware interlock is backed up by a matching software interlock –The low-level software interlocks are avoided by the configuration state machine Shutter interface with SAAO detector subsystem is final
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Mar 18, 2003PFIS CDR5 Control System Heat Budget Steady-state heat is all in cooled boxes; 400 W is well below PFIS allocation of 1.3 kW Primary source of uncooled heat is motors Most motors have very low duty cycle, and are not used during observing; time-averaged power is about 1 W Exceptions are polarimetric modes - in the high-speed shuffle modes, duty cycle can be very high. For a 25% duty cycle, add 0.8 W for linear and another 0.8 W for circular.
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Mar 18, 2003PFIS CDR6 Control System Motors and Drivers 8 axes of motion control 2 NI 7334 cards (1 spare) 4 Oriental Motors (with drivers) 2 embedded (OEM) motors 1Slo-syn high torque motor for articulation 1 DC stepper mike for focus
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Mar 18, 2003PFIS CDR7 Control System Software Block Diagram Client/server design Client sends text strings Server runs mechanisms 3 levels of server software: actuator level mechanism level procedure level Interlocks are built in at all levels
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Mar 18, 2003PFIS CDR8 Control System Software State Diagram Operational complexity has been tamed Maximum time to reconfigure: spectroscopy to Fabry-Perot Imaging. This is driven by two mutually exclusive operations Other operations can be done in parallel
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Mar 18, 2003PFIS CDR9 Control System Software Development Plan All LabVIEW: no custom C code needed Top-down design –Create LabVIEW type-def data base (data clusters & enumerated commands) –Get astronomer and operator feedback on GUI pages & navigation –Rapidly prototype & use GUI Bottom-up implementation –Code & debug actuator wrappers –Integrate & test actuator wrappers at mechanism level –Assemble mechanism VIs into operational procedures Document each VI as we go –Use LabVIEW documentation process –Place text boxes on diagram Configuration management: use LabVIEW version control
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Mar 18, 2003PFIS CDR10 Control System Software Integration & Test Plan Match LabVIEW coding sequence to mechanism fabrication LabVIEW modules are ready as mechanism comes on line Bench testing of mechanism & control software happen together Develop mechanism acceptance test procedures during mechanism I&T Debugged mechanism software modules get used in high level observing procedures High-level procedures will include short- and long-form test procedures
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Mar 18, 2003PFIS CDR11 Control System State Transition Table Table-driven state machine provides 3rd level of interlocks, in addition to hardware interlocks & actuator-level software interlocks Table prevents PFIS from being driven into a bad state “State detection” is part of startup & error recovery - figures out what state PFIS is in
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