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 Mar 18, 2003 PFIS CDR

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) Mar 18, 2003 PFIS CDR

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. Mar 18, 2003 PFIS CDR

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 Mar 18, 2003 PFIS CDR

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. Mar 18, 2003 PFIS CDR

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 Mar 18, 2003 PFIS CDR

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 Mar 18, 2003 PFIS CDR

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 Mar 18, 2003 PFIS CDR

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 Mar 18, 2003 PFIS CDR

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 Mar 18, 2003 PFIS CDR

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 Mar 18, 2003 PFIS CDR