The Generic Pixel Server (GPX) Dictionary A common command set for image acquisition N. C. Buchholz P. N. Daly (NOAO) Copyright, 2004 © AURA, Inc.

Introduction Background The Goal GPX Communications GPX Command Set Attribute-Value Pairs Image Data Handling Future Developments

Background Nov. 2001 ACCORD conference outlines GPX concept, Santa Cruz, CA Feb. 2002 GPX definition proposed at AURA Software Conference, Baltimore, MD Mar. 2002 MONSOON Software Design started, NOAO, Tucson, AZ Aug.- Sep. 2003 First light on MONSOON Systems, Tucson, AZ & La Serena, Chile

MONSOON Team August, 2003 L to R: Peter Moore, Dee Stover, Paul Schmitt, Dave Dryden, John Garcia, Jerry Penegor, Nick Buchholz, Phil Daly and Dave Sawyer. (Not shown: Gustavo Rahmer, Mike Warner, Ricardo Schmidt, Mark Hunten).

MONSOON Results 8 August 2003: First Light Aladdin_III 19 September 2003: First Light Hawaii II 29 September 2003: First Light CCD

The Goal Astronomical images as easy as digital photography

The MONSOON Image Acquisition System An Extensible architecture. Defined by Interface Control Doc’s at each level. Based on COTS Technology and a small number of reusable in-House boards. Not tied to a specific hardware set. Designed for large pixel count detectors & Mosaics. IR FPAs, CCDs, OTAs, Allows for digitizing Focal Planes. Allows for re-packaging of electronics. Three Level System. MSL - Single control point for the entire focal plane. PAN - Intelligence for a section of the focal plane. DHE - Low-level Hardware control for a section of the focal plane.

The MONSOON Image Acquisition System

The Generic Pixel Server (GPX) Isolates focal plane control from: Telescope control. Instrument mechanism and temperature control. Data archiving (the DHS mechanisms). User GUI’s and Status displays. Significantly reduces the complexity of the software. No functionality is lost.

GPX Communications Simple socket-based communications. Bi-directional message based. Multiple connections permitted. ASCII text based commands & responses. Small number of fixed formats. Designed for simple response parsers. Provides for Unique command id. MONSOON Uses - MONSOON Star Date (MSD) - accurate (to 1s) time stamp based upon Julian day plus gettimeofday() function. Interface calls for 8 ASCII bytes for ID.

GPX Communications (Cont.) Provides for asynchronous event handling. Power glitches, spurious resets. Communications failures. Detector voltage changes. Exposure completion. GPX system can require asynchronous event response. Insures Client software catches events. Allows info only events (for status reporting).

GPX Command Set - System Set-up. gpxSetMode - general purpose set-up command. Set-up selection is by mode name. <SAVE> allows automated mode creation. gpxSetMemCfg - DHE Memory configuration. Loads memory addresses without error checking. Used for waveform sequencer program & patterns. gpxSetAVP - Set Attributes to desired values. PAN checks for value range errors. PAN checks for data lock-outs. Redundant commands - add convenience. gpxSetArrCfg, gpxSetExpCfg, gpxSetIdpCfg.

GPX Command Set - Exposure Control. gpxStartExp - starts an exposure sequence. All PAN/DHE pairs synchronized by hardware. Controls local shutter if available. Handles integration timing accuracy determined by DHE hardware. gpxWaitForTrigger - arms the DHE sequencer Same functionality as gpxStartExp Sequencer waits for hardware trigger signal. gpxPauseExp, gpxResumeExp - May be NO-OPs for certain systems (IR FPAs) gpxStopExp, gpxAbortExp

GPX Command Set - Info, Status & State. gpxGetState - reports the state of the PAN/DHE. Response determines range of allowed actions. gpxGetAVP - reports the value of an Attribute. Directives allow range and permission checking. Return could report value out-of-range as well. gpxAsyncMsg - unsolicited message reporting event. May require response from upper level. Built-in to several levels of system. gpxAsyncResp - upper level response to gpxAsyncMsg.

GPX Command Set - Hardware Controls gpxPower - control for power to GPX systems. Systems may elect not to provide this control. Can be used to control voltages to detector. gpxReset - multi-level system reset . Provides board level warm and cold re-start. Provides Fiber channel reset, DHE reset, possible PAN process reset. gpxShutter - sets local shutter control state. Normally sets shutter state for subsequent exposures. immediate directive (<IMMD>) controls shutter NOW. gpxShftImg - send an image shift command to DHE. provided for control of OTAs and Shift-and-Add systems.

GPX Command Set - Miscellaneous Debug and Test gpxDebug, gpxSimulate, gpxTestMode gpxPass Meta-Commands gpxHelp, gpxDump gpxExit, gpxShutdown GPX Client Library connectGPX, disconnectGPX, sendGPX, recvGPX asyncRespGPX

Async Messages and Responses Used to deal with asynchronous or unexpected events. Available at each interface level. Allows synchronization between levels. (rendezvous.). Allows automated error recovery. Allows Client/upper levels to act on low level events. No additional out of band protocol required.

Future Developments Complete additional “Use-Case” reviews to insure the Dictionary is complete. Complete NOAO ICD 4.1 to describe the MONSOON implementation of the GPX. Complete the description of the Status Reporting and DHS interface libraries. Use the GPX dictionary to complete the implementation of NEWFIRM, IR and CCD LAB, OTA test, Science & Engineering Client systems. Complete Implementation of the Client-GPX Interface Library.

Papers at SPIE ... N. C. Buchholz and P. N. Daly, “The MONSOON Generic Pixel Server Software Design”, 5496-41. P. N. Daly and N. C. Buchholz, “The MONSOON Implementation of the Generic Pixel Server”, 5496-42. P. N. Daly, N. C. Buchholz and P. C. Moore, “Automated Software Configuration in the MONSOON System”, 5496-43. N. C. Buchholz and P. N. Daly. “The Generic Pixel Server Dictionary”, 5494-20. R. G. Probst, N. Gaughan, G. Chisholm, P. N. Daly, E. A. Hileman, M. Hunten, M. Liang, K. M. Merrill and J. Penegor, “Project Status of NEWFIRM: the Wide-field Infrared Camera for NOAO 4m Telescopes”, 5492-124.