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SkyWalker Client Interface Specification and Programming Guide

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1. Copyright Astrometric Instruments Inc 10 Ox9D Ox9E Ox9F OxAO OxAT OxA2 OxA3 OxA4 OxA6 OxA7 OxA8 OxAA ATCL_INTERNAL_ERROR ATCL_SYNTAX_ERROR ATCL_IDC_ASYNCH ATCL_VERIFY ATCL_FRAMING 1 ATCL_COMM_OVERRUN 1 ATCL_CMND_OVERRUN 1 ATCL_CMND_TIMEOUT 1 ATCL_ID_CMND ATCL_ID_LINK ATCL_ID_DING ATCL_CHANGE_NOTIFY Character preceding an internal error asynchronous message ie SkyWalker software or hardware failure When an internal error occurs SkyWalker is halted and a power cycle is necessary All subsequent ATCL commands to SkyWalker will result in a repeat of the internal error asynchronous message The Client should cease sending commands following reception of an internal error and instruct the user to power cycle SkyWalker There was a syntax error in an ATCL command The offending command lacking l prefix and 5 termination characters is returned verbatim between the ATCL_SYNTAX_ERROR special character and semicolon termination character Character preceding a to Instrument Display asynchronous packet Described in the Instrument Display asynchronous responses subsection below Used when verification is needed from the Client See ATCL Verify section below There was a communications framing error There was a communications buffer overrun A new command was received prior to completion of the last command or prior to the full transmission of the last command s rep
2. oc tope e t tite e ia eee tte ESEE E ERNE KEE EEK E ii 2 10 Client software design implications aieo t b RO eie Ec Nee DD e E le e e eor s 2 10 1 Client commands must take turns eee p EE ee E eene tenet eten ete tte te tenente ene tente eben tento tenentes te tente bee nba se ondoree susteren 2 10 2 R cerve asynchronous messages eese epe oe eet oe c e RR RUD EUR PUE REOS 2 10 3 Start by getting out of ACL mode and checking SkyWalker s firmware version 2 10 4 Properly handle error conditions eene ual RR eeens orsin eroe rere E ennt tentent nrnna Erste tte t ttn eene tentat rn eiiie tentent 2 10 5 Managing SkyWalker s presence ceterae ir nde Re ere e e tsb dh AER e e Re rbd e ERE ieg EERE SEa 2 10 6 Implement an Instrument Display interface see 2 10 7 Characters to disallow in strings from the user 2 10 8 Be aware of ATCL s timeouts essere ttt tenente tenentes ATCL Command Reference eese tenente ttt sesos enne tenentes 3 1 Command group list seen ee aenea e 3 2 Command Notes and CONVENUH ONS ERES DO M 29 2 1 3 NOLES ses epp ep rH EOD eto Be EID RR RH PE REPRE E tr rre RE RR ERR Ere RR br tdg RR 33252 Conventions MED Em BLISS 32 3 Additional conventions soot NI eere ODE RT Laas er URN RAP E
3. Arcseconds Copyright Astrometric Instruments Inc 49 ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or Command name Code return Description Gear backlash error correction SetBLashEnabledX MSbx FLAG Turns on Yes or off No backlash correction for the X axis Turns on Yes or off No backlash correction for the Y axis n e Seetu M Velocity that backlash correction is applied in X between 1steps sec to 30 000steps sec ee ee Velocity that backlash correction is applied in Y between 1steps sec to 30 000steps sec SetBLashCorrMagX MSmx NN NNNsteps Magnitude of backlash correction applied in X between 1 and 30 000 SetBLashCorrMagY NN NNNsteps Magnitude of backlash correction applied in Y between 1 and 30 000 GetBLashCorrAppliedX MGfx NN NNNsteps The present backlash correction applied in X Listed as number of motor steps GetBLashCorrAppliedY NN NNNsteps The present backlash correction applied in Y Listed as number of motor steps ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or Command name Code return Description Gear Period SetGearPeriodX MSix NN NNN Number of motor steps in X to rotate the gear once Min of 100 max of 99 999 998 GetGearPeriodX MGix NN NNN Number of motor steps in X to rotate the gear once Min of 100 max of 99 999 998 GetGearCount
4. GetMotorPolarityX MGpx SIGN Returns Positive or Negative SetMotorPolarityY MSpy SIGN String Positive or Negative GetMotorPolarityY MGpy SIGN Returns Positive or Negative Parameter or Command name Code Description SmMaoGePeReX mss NNN mnooo emoosesonox me in 000000000 GeWooSwpsPeReYT Ma win T ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature Copyright Astrometric Instruments Inc 47 Parameter or Command name Code return Description Motor status amp diagnostics a Ls onc ee Genii MG c Rus crt retro IW SANS GelMoorveY MGw Returns current motor velocity in the format SNN NRNsIepE sec Gm Mx T Se a My 1 CO C Wax WU OlswWsmsusZUWosORPiKOmmd ZachiDagPostonk Wa ces Zs fan Pe Woonark comer Zeros resets the MotorDiagPositionY counter Parameter or Command name Code return Description Gear periodic error correction settings and status SetPECorrEnabled MSpe FLAG Enables disables periodic error correction GetPECorrTrained MGpt FLAG Returns Yes if periodic error correction is trained No otherwise GetPECorrAppliedX SNN NNN Returns present magnitude of Xaxis periodic error correction in the range of 32 767 32 768 Indicates command supported
5. SetHomelndexY DiscoverDir commands and need to be consistent with the directions used for HomeDiscover AtHome and HomeSeekError are cleared if this command successfully starts the seek operation AtHome is set and SkyWalker sets its Axial coordinates to the index coordinates discovered and saved with the HomeDiscover command if this command successfully completes the seek operation The Client can then submit an AlignFromHome command to complete the Align from Home Index Seek operation HomeSeekkError is set if this command is unsuccessful Note this command requires that Automation Modules are in the system peu ccc If the telescope has not moved since successful completion of the last HomeSeek command then returns Yes otherwise returns No AlignFromHome none Same as AlignFromLast but requires that AtHome is asserted After a HomeSeek is completed it is recommended that this command be used to align the telescope Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature 3 4 Coordinate commands Parameter or 2n Command name Code Exe Description Coordinate status HOURS Returns HOURS or N A if not yet aligned SIGNED 2DIGIT Returns SIGNED 2DIGIT or N A if not yet aligned GetHourAngle HOURS Returns HOURS or N A if not yet aligned UNSIGNED 3DIGIT Returns UNSIGNED 3DIGIT or N A if not yet aligned SIGNED 2DIGIT Returns SIGNED 2DIGIT or N A if not y
6. OverCurrentRA OverCurrentDec OverSpeedRA OverSpeedDec None Note for Alt Az mounts RA is replaced with Az and Dec is replaced with Alt ClearEventFaults HCef lt none gt Clears event faults Event faults are associated with SkyWalker Servo and are set in the hardware and require clearing from the user Event faults include StallRA Dec OverCurrentRA Dec OverSpeedRA Dec Note for Alt Az mounts RA is replaced with Az and Dec is replaced with Alt Copyright Astrometric Instruments Inc 33 HardLimitOverride HHlo none Requires installation of Automation Module to operate When this command is issued the Automation Module will override deassert SkyWalker s HardLimit input for 5 seconds With this command a remote client can back out of a HardLimit condition in a controlled manner that does not require on site operator intervention For more details see the Automation Module User s Manual DOC 14 HardLimitBackOut lt none gt Requires installation of Automation Module to operate When this command is issued SkyWalker will attempt to move out of a HardLimit condition The specific sequence that this command follows is 1 Find first active Axial Limit in the sequence East West Up Down If the positive and negative Axial Limits are both asserted for either X or Y then exit with Both Axial Hard Limits in the X Y axis engaged cannot back out
7. TOR QN RU P OD RR RN RR E DEREN 3 3 Alignment and Calibration commands Bf mam esecsscsesnssencussesenvensuesesvovsnvnssessesssedssssnenssvevsvenvavenseessessestonsavavevensestusussbassesnecendsnsseseevevasssesssonesnssessenssedsasensuenesbsvancnesesoesdsedeesenanea 3 4 Coordinate commands eit mto Nelle be eere Reden eripe eet d Utt ar RU e tbt dn eite ien Ore Os 3 5 EnCoder COMMANGS EESEERE EIS om uum Jp EE 3 6 Preference commands oso Mao BURNER C rU DURUM ED RUE Ct ERO OR RE Ur D ORUM 3T G Toc mmand Ss oc EE E IL c 3 8 Hardware commands Miu mee OR ORI D EIFE RENE OM HEU UFU UR RP EO ke De Ub tr UP S rr RR Ue EDU UE 3 9 Instrument Disp laymen man m Br AA 3 10 HandPaddle and A ut immtler coruunds edP ODER ERU TIPO ERA Pre Eep P S R Ra EAEE T TEER ERa E REEPERI 3 11 Tite tools A ale eee eese h 3 12 Motor and gearing commands sessseseeeeenenn ete ttetntenent nnt ten entente Special topes ssvassescceves Ju Copyright Astrometric Instruments Inc 3 EN PE ani Alignment Wizard nM 4 2 Instrument Display nterface o eet epe e Pe o rere teet eap ns fee ee rpm RS 4 2 1 Instrument Display CUTE CER s DOTEM 4 2 2 Instrument Display asynchronous TESPONSES i c 3 err PU DR EU te ber PERRA ete Er a te b
8. be no bandwidth limitations with ATCL running at the specified 19 200 baud rate however there could be severe latency issues in a Windows based Client To address the Windows latency issues ATCL provides the Static Status Change Notification and Status Aggregates features as described in the next sections Copyright Astrometric Instruments Inc 11 12 2 4 Static Status Change Notification To reduce the communications bandwidth overhead of updating static status and mitigate the need to continuously poll for updates SkyWalker includes a static status change notification feature The way this works if enabled is that whenever static status changes an asynchronous reply indicating what has changed and to what value is sent to the Client This feature is the complement to Dynamic Status Aggregates see section of that name for details Aggregates are a lower overhead way for Clients to poll SkyWalker s dynamic status The static status change notification feature is a very low overhead way for Clients to receive notification of changed static status Static status is status that is not dynamic and does not change regularly Static status only changes when a user makes a change Since SkyWalker has multiple user interface inputs e g handpaddle Client port a mechanism to notify the Client when a static status change occurs is a useful alternative to polling The gatic status change notification feature is enabled after th
9. converts this to sensor temperature please contact Astrometric Instruments Returns four characters 1234 where each character can be 0 inactive or 1 active First character 1 HomelnLimit state Second character 2 OutLimit state Third character 3 Driver over temperature state note if over temperature is detected the driver will shutdown until power is cycled Forth character 4 AtHome bit See FocusHome command FocusPro initiates a four step home finding sequence Step1 move out fast until home switch not active Step2 move in fast until home switch found Step3 move out slow until fully accelerated and home switch not active Step4 move in slow until home switch found In step 4 when home is found all motion terminates and the AtHome bit is set read with the GetFocusLimitsAndFaults command HEX Parameter is step position gt 0 or lt SFFFFF to go to GetFocusProFirmwareVersion nn e r Returns FocusPro firmware version GetFocusDebug HGig gt Returns an arbitrary string used for engineering debug purposes 38 Copyright Astrometric Instruments Inc k Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or Command name Code Description SetIndicatorBrightness HSib NN Brightness is between 1 and 15 SetIndicatorOnTime HSio SECONDS 0 075sec to IndicatorPeriod SetlndicatorPeriod HSip SECONDS IndicatorOnTi
10. is necessary to send the SetAlignmentStartingPosition command with None as a parameter previous paragraph and go back to step 3 so that the user is prompted for the side of the sky to align from When the user clicks Next send the AlignFromStartingPosition command to SkyWalker At this point SkyWalker should have an Alignment State of Preliminary unless they choose a Starting Position of None in the previous step in which case SkyWalker will remain un aligned for now Provide a screen with suggested title Choose alignment star with a scrollable list of alignment stars This list can either be consistent with SkyWalker s bright star list or the Client s own custom list Include instructive text e g Select an alignment star from the list Use the ATCL object database commands to get this information if using stars consistent with SkyWalker s bright star list After the user clicks Next provide a screen with suggested title Alignment star information that shows important information on the star selected e g Magnitude Altitude and Azimuth Also on this screen provide GoTo and AlignOnStar buttons If the user clicks GoTo and the Alignment State is at least Preliminary use the GoToSelectedObject or GoToTargetRA_Dec commands This should slew the telescope near to the selected star Note as with any GoTo the GoTo progress bar should be displayed while the GoTo is in progress If the user clicks the AlignOnSt
11. last visited non hidden Display Map node as yellow 4 2 2 Instrument Display asynchronous responses When SkyWalker needs to change the contents of the Client s Instrument Display it sends an asynchronous packet preceded by the ATCL_IDC_ASYNCH special character The packet contains a return command that the Client must act upon to assure that the contents of the Instrument Display remain up to date Note the string xxxxx in the below table is of variable length Packet string C Overwrite field text in field f with characters xx f is in the range of 0 through 7 8 fields If any character in xxxxx is preceded by 08h it is drawn in reverse video Note xxxxx should fully overwrite text in field f No original text should be left in the field even if xxxxx is shorter than what was in the field Ofxxxxx Menu button is live menu buttons 1 7 correspond to bits 0 6 in w Note bit 7 of w is undefined It may be 0 or it may be 1 so as not to cause u to ever be NULL Note there is no menu button 0 There is a field 0 it is the top field of the display for which there is no button Scroll up n lines i e move field x to field x n if possible where x is between 1 amp 7 Necessary action Clear the Instrument Display Copyright Astrometric Instruments Inc 57 58 Dn Scroll down n lines i e move field x to field x n if possible where x is between 1 amp 7 Exoxx Fill e
12. the SkyWalker to Client return packet yet The Client should implement two timeouts to guard against a hang in either of these events 1 A command reply timeout checks that a command is replied to A reasonable limit of say 1 second for a completed command reply is suggested Any longer than that and there is likely something wrong with the communications with SkyWalker 2 An asynchronous message completion timeout would signal that the start of an asynchronous message was received however the semicolon termination character was not received in a reasonable time e g 1 second Upon detection of a timeout it is suggested that the Client go into a looking for SkyWalker mode where a benign command is regularly send to SkyWalker e g CommEcho or GetSkyWalkerSoftwareVersion If an error free response is received then the Client can leave the looking for SkyWalker mode and carry on Note these measures are particularly important in the no guaranteed latency environment of the Microsoft Windows operating system 2 10 6 Implement an Instrument Display interface Copyright Astrometric Instruments Inc As described in the Instrument Display interface section below ATCL includes a sub set of functionality that exposes SkyWalker Instrument Display interface It is recommended that any SkyWalker Client application that is designed to provide full exposure to SkyWalker s features expose the nstrument Display interface and properly de
13. then should not send another command until it gets a reply from the first command There are no reply less ATCL commands This is necessary for system integrity and Client management and tracking of which reply or return value is for which command SkyWalker also requires the full reply approach to assure that it can handle ATCL traffic under all conditions i e SkyWalker can delay command processing if necessary to complete another higher priority task Note if the Client sends another command before the former completes then SkyWalker sends an ATCL CMND OVERRUN message more on messaging below Return values always take one of three forms note special characters presented here are defined in the following sections 1 Reception of the command was successful however there was no return data e g not a status command In this case the single special character ATCL ACK is returned Note there are additional single character return values for commands from the Instrument Display ATCL command subset as described in the section of that title below 2 Reception of the command was successful and there was return data e g a status command In this case a string terminated with the semicolon character is returned The string contains the results of the status query The string is always terminated with the semicolon character ATCL syntax uses the semicolon character only as a string termination character 3 Reception of the comma
14. through SkyWalker s Static Status Change Notification SSCN feature Parameter or Command name Code nefurn Description Gear periodic error correction training 48 Copyright Astrometric Instruments Inc StartPECorrTraining MSpt none Starts PEC training if the following conditions are met Mount is polar aligned ViewVel1 is specified ViewVel1 is less than 15 arcsec sec so as not to cause RA backlash while training Alignment is complete TrackRate is Sidereal MoveMode is Track ViewMode is PanScope so that keyed movement is along telescope axes GearPeriod is not too large for PEC CancelPECorrTraining MCpt Cancels PEC training SavePECorrTraining MScb lt none gt PEC corrections are saved to SkyWalker s Flash memory Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or Command name Code return Description Gear periodic error measurement StartPEMeasurement lt none gt Starts periodic error measurement if the following conditions are met Mount is polar aligned ViewVel1 is specified ViewVel1 is less than 15 arcsec sec so as not to cause RA backlash while training Alignment is complete TrackRate is Sidereal MoveMode is Track ViewMode is PanScope so that keyed movement is along telescope axes GearPeriod is not too large for PEC CancelPEMeasurement Cancels periodic error measurement GetPEMeasurementDrift MGmd sDDD
15. 2 Signal the Automation Module to override SkyWalker s Hard Limit input for 5 seconds 3 Issue an Axial GoTo with a destination that is 2 degrees inside the limit found in step 1 4 After completion of GoTo and 5 second Hard Limit override delay if Hard Limit is no longer asserted then exit the sequence quietly otherwise exit with Axial Hard Limit still asserted after back out has completed Note if no Hard Limits are active or if SkyWalker is still in a previous Hard Limit back out sequence this command does nothing Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or NN Command name Code aet Description Axial Hard limits GetAxialLimitEastActive Hise FLAG Indicates if East Axial Limit is active GetAxialLimitWestActive Hisw FLAG Indicates if West Axial Limit is active GetAxialLimitUpActive Hisu FLAG Indicates if Up Axial Limit is active GetAxialLimitDownActive Hisd FLAG Indicates if Down Axial Limit is active SetAxialLimitEastAngle HSae DEG Angle measured to the East of the celestial meridian SetAxialLimitWestAngle HSaw DEG Angle measured to the West of the celestial meridian SetAxialLimitUpAngle GN measured Up from the Scope Equator Copyright Astrometric Instruments Inc SetAxialLimitDownAngle HSad DEG Angle measured Down from the Scope Equator SetAxialLimitEastWestEnabled Sew FLAG String Yes to e
16. 3 FLAG String Yes to set Momentary output and No to clear 40 Copyright Astrometric Instruments Inc Toggle ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or Command name Code Description Autoguider GetAutoGuiderState Returns a four character string where each character is 1 or 0 depending on weather the associated AutoGuider input is active or not Encoding Character Direction indicated Up Down Left Right For example 0101 means that Down and Right are active Parameter or Command name Code Description HighDrive assignments LLL NNNML NEU NN RR NN LUN LUNNML ee LUI NEL NL I MN NN i Ui ULL MN es Copyright Astrometric Instruments Inc SetUniDriveA Assignment HSua see below emona sonen fre ee RN LLLI G NE MN NN Saunt Armen ew umida 000 EIL C LNNMLINE NN NR NNNM LII LL MN NN BELLI CL NNNL NEU MN RR NN monoko oa e MN NCC NN For the above commands the Alarm AlwaysOff AlwaysOn DewHeater1 DewHeater2 DewHeater3 DomeDir DomeDrive FocusDir following assignment parameters FocusDrive Indicator MapLight Momentary1 Momentary2 Momentary3 OneShot Timer Toggle1 apply Toggle2 Toggle3 ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or seats Command name Code return Description HighDrive diagnostics SetDiag
17. Axial Encoder Track Lock feature enoe e FAG eeen fe sn Sanopa esy sw Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Target coordinates SetAxialEncoderTrackLockEnabled FLAG When AETL is enabled the error desired position encoder position is continuously calculated When this difference exceeds 1 encoder count then motor steps are added to catch up the telescope axes as measured by encoder position with desired position GeWisEndeTacLokEnabed EQ FIRST 28 Copyright Astrometric Instruments Inc Parameter or 2n Command name Code C erar d iem Description SetAxialEncoderTrackLockCorrX ESax NN NNN Number of motor steps to correct X motor position when a discrepancy with encoder position is detected Default value is 1 and max is 10 Note this value can be set to 0 and then GetAxialEncoderTrackLockErrorX used to view un corrected motor encoder error SetAxialEncoderTrackLockCorrY ESay NN NNN Number of motor steps to correct Y motor position when a discrepancy with encoder position is detected Default value is 1 and max is 10 Note this value can be set to 0 and then GetAxialEncoderTrackLockErrorY used to view un corrected motor encoder error GetAxialEncoderTrackLockCorrY INNNN NNN SetAxialEncoderTrackLockCadence Fa NNN Number of Ticks 75 milliseconds between Number of Ticks 75 milliseconds between application of corrections of correctio
18. Guider commands Parameter or Command name Code Bef in Description lt none gt Removes handpaddle from i Mode takes it out of Mode StartPersistentUp Accepts a string with 0 to 100 representing 0 100 of the current max velocity i e VelMax for Slew and current ViewVel for View A string of 101 signals SkyWalker to hold the current velocity if accelerating Copyright Astrometric Instruments Inc 43 StartPersistentDown KSpd gt See StartPersistentUp StartPersistentLeft KSp h gt See StartPersistentUp StartPersistentRight KSpr gt See StartPersistentUp View motion settings SWR Ki FUG ve Lat an igh arpa aore n noe BsWewwwiEwie FLAG awe Yor Wenadedand No Tae O SetViewMirrorEnabled KSv FLAG String Yes to enable and No to disable GetViewMirrorEnabled KGvw FLAG es Returns Yes if enabled and No if disabled Saione KS MENDAGGEL MnwoSHimssznsro ena X or asin woh sTo SetViewMode sme A PanScope or PanRA Dec note only PanScope is supported in present SkyWalker firmware GetViewMode KGym See SetViewMode SetViewVel1 KSvi VIEW VEL Min of 1 0000asec sec max of ViewVel2 GetViewVel1 KGvi VIEW VEL dB MM IS Seiewe Ks pwya pnv Vew Saves koa ewy fina Veee ma Voa OO Gevew r Kad pewa o GelVewved ksa MIEW YEL in o vewe maro zOndegsecVeMKor Valex whichever s ower peewee RG EWE Sammecudevl A ino 0tdsecc mer Zones Vino Vain who
19. HighDriveEnabled HSdh FLAG String Yes to enable and No to disable DiagToggleBiDriveA Does nothing if HighDrive diagnostics is disabled DiagGetBiDriveA_State HDba FLAG DiagToggleBiDriveB HTbb Does nothing if HighDrive diagnostics is disabled DiagGetBiDriveB State HDbb FLAG ce LILLIIMMML INL MM NN L LLILINMLINL MN NN 42 Copyright Astrometric Instruments Inc DiagToggleUniDriveD HTud none Does nothing if HighDrive diagnostics is disabled ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature Momentary Parameter or Command name Code return Description GetInSystemAggregate1 Returns HP1_ Present HP2_Present HREMX_Present HREMY_Present AutoModX Present AutoModY Present in the format FLAG FLAG FLAG FLAG FLAG FLAG GetInSystemAggregate2 Eoo emat DomeProPresent FocusProPresent FilterProPresent SwitchProPresent in the Coo mat FLAG FLAG FLAG FLAG GetHardwareAggregate1 nil Returns SkyWalkerSupply Voltage SkyWalkerSupplyVotlageStatus AutoGuiderState TopActiveFault TopLimitViolation AutoModX Auxln and AutoModY Auxln in the format XX Xv sss UDLR ffffff llllil hFLAG FLAG GetHardwareAggregate2 Returns AxialLimitEastActive AxialLimitWestActive AxialLimitUpActive AxialLimitDownActive in the format FLAG FLAG FLAG FLAG 3 9 Instrument Display commands See the sub section in section 4 titled Instrument Display interface 3 10 HandPaddle and Auto
20. SkyWalker Client Interface Specification and Programming Guide Copyright 2004 2008 Astrometric Instruments Inc Last revision date 23 Dec 2008 Copyright Astrometric Instru ments Inc This document can be ordered as Astrometric Instruments part DOC 11 Copyright Astrometric Instruments Inc 4 Contents 1 Basic MN Ctidmial OVELVICW d e P MM eM RERO DE E 6 TT Protocol Introd ction s ente RERO URN rU D REP va loving ent DER rd tte pe ebbe erem 6 1 2 ATCL Command Syntax introduced eiie einer detenti tette te tetentese tt tet e ei s t i e mb reete tienen te etienne nes 6 Advanced functionality E UD PR RR P EROR C MPO re P Me irse de bedupe v eb PeeDe eR 8 2 1 Asynchronous Messaging 2 2 S pecial characters de RO t RR Ire ROREM 2 3 Bandwidth and latency requirements seen 2 4 Static Status Change Notification tenente tentes 2 5 Status A GPE Bates ee e e RR E Re e e E RT e b dee RTT Ean 2 6 A TCTZ Venfy Lied eoo oe edt Rte RR UU MERI id DRE opea eren dr ella romeo e ene OPER eR RR HERR 227 SWOSUUI I ER e AO e SEE EE ER E EERE RER 2 0 E ImeQouts 3 EEEE O CE O AEAEE ETAT TE NUES E a aaa i a a a a Bob coh a aa eae oea ES i i Miaa E 2 8 2 Chent update timeout tete eer tere EAE Me MMs LE AA EEE EE ETET 2 9 Serial COMMUNICATIONS settinigs
21. VelocityX AxialVelocityY in the format FLAG oooo00 SIGNED 3DIGIT REAL SIGNED 3DIGIT REAL XX XXdeg sec XX XXdeg sec where oooooo is Primary or Secondary ndicates command mp NN through p Static Status Change Notification SSCN feature Parameter or Command name Code retum Description Target coordinates SetTargetDec CStd SIGNED 2DIGIT Note be certain that the correct EpochOfEntry has been set with the SetEpochOfEntry US GetTargetDec CGtd SIGNED 2DIGIT SetTargetRA HOURS HR EEENNr be certain that the correct EpochOfEntry has been set with the SetEpochOfEntry ee EN NN NNUS russe csse aig target Observed not Apparent Altitude Sets target Observed not Apparent Azimuth DGwWmww E wswoxp Copyright Astrometric Instruments Inc 27 3 5 Encoder commands Parameter or 2A Command name Code 7 Te Description Encoder settings SeenccaerCounsPerRex Eses NNNNN accepere s0988 O OOOO GeEdewOnmsReRRKT EG u O T GetEneoderounsPemey Ed NNN SetEncoderEnabledX FLAG If Yes then the X encoder is enabled for use with the CalFromEncoder feature see CalFromEncoder command in Alignment and Calibration commands section and the Axial Encoder Track Lock feature SetEncoderEnabledY ESny FLAG If Yes then the Y encoder is enabled for use with the CalFromEncoder feature see CalFromEncoder command in Alignment and Calibration commands section and the
22. X MGux NN NNNsteps Gear position in X in steps measured from last Gearlndex detection ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature 50 Copyright Astrometric Instruments Inc Parameter or Command name Code return Description Gear Index SetGearlndexEnabledX MSex FLAG Enable disable use of Gear Index on X axis to zero GearCount once per gear rotation GetGearlndexEnabledX MGex FLAG GetGearlndexToggledX MGax FLAG Toggles every time a Gearlndex detection occurs on the X axis GetGearlndexSincePowerUpX MGox FLAG Indicates if a Gearlndex has been detected since power up on the X axis SetGearlndexHysteresisX MShx NN NNNsteps X axis offset between Gearlndex position moving positive vs moving negative GetGearlndexHysteresisCountX NN NNNsteps Measured diagnostics X axis offset between Gearlndex position moving positive vs moving negative SetGearlndexGateEnabledX FLAG Enables use of gating signal if SkyWalker model supports it which is logically ANDed to the Gearlndex signal GetGearlndexGateEnabledX MGgx FLAG GetGearlndexGateStateX MGix FLAG Reports the state of the GearlndexGate input if SkyWalker model supports it ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or Command name Code return Description Motor and Gearing aggregates GetMotorStatAggregate gt Returns Motor Diag Po
23. al format FocusPro does not directly accept decimal values FocusSlowPulse rarene FS Gees GH SELL NN NN Garoassowrae AN raran SP Gerosa pe LLL NNNM NN wes pe SL NN wem KR passon pe Hamm Wa a WHe paster p Feassowruse p SetFocusMaxVel Bounded to a hexadecimal value of 1 to 80 80 hex is 128 decimal A value of 128 decimal is equivalent to 32 000 microsteps per second All other legal values scale linearly GetFocusMaxVel Copyright Astrometric Instruments Inc 37 SetFocusAccel HSfa HEX GetFocusCurrentReduction GetFocusPosition GetFocusTemperature GetFocusMoveMode GetFocusLimitsAndFaults FocusHome none FocusGoTo 7 Bounded to a hexadecimal value of 1 to FF FF hex is 255 decimal A value of 255 decimal is equivalent to acceleration ramp to full speed i e 32 000 microsteps second in 0 512 seconds All other legal values scale to a ramp time inverse linearly smaller acceleration leads to larger ramp time in reverse linear manner Sets the current reduction when idle for more than 150 milliseconds Choices are 1 no reduction 2 1 2 current 4 1 4 current or 0 motor de energized after 150 milliseconds Note if O is used then the motor rotor position will move to the nearest full step and only motor detent torque will persist Returns FocusPro s temperature Analog to Digital converter value in the range of 0 FF 0 255 digital For the conversion table which
24. al with the extra single character return codes that the nstrument Display provides Astrometric Instruments open source Maestro Lite program is an example of a Client that provides an Instrument Display interface 2 10 7 Characters to disallow in strings from the user The characters and have important syntactical use in ATCL and or SkyWalker internals as prefix and command string termination gt 9 epo characters Client software should assure that no extraneous or characters are present in command strings It is of particular importance to filter out characters otherwise a user could inadvertently enter an character in for example a site name If the Client software did not remove it then the command exchange between SkyWalker and the Client would be mis sequenced 2 10 8 Be aware of ATCL s timeouts The Client must send a complete command within the 1 second command timeout i e from reception of to reception of must be less than 1 second otherwise the command will be lost and an ATCL CMND TIMEOUT error will occur To disable this timeout use the DisableCommandTimeOut command The Client must send a command to SkyWalker at least every 5 seconds otherwise SkyWalker will disable its Asynchronous Message reporting i e updating to the Client Reporting is re enabled upon reception of any command To disable this timeout use the DisableUpdateTimeOut command As mentioned in t
25. ar button send the AlignFromSelectedObject or AlignFromTargetRA Dec command to SkyWalker Note if using the AlignFromTargetRA Dec command be sure to use the SetEpochOfEntry SetTargetRA and SetTargetDec commands first Copyright Astrometric Instruments Inc 53 54 10 If the Alignment State is still Preliminary then repeat from step 6 since a second star is needed to complete alignment Note it might be useful to title the screen associated with the 2 pass through step 6 as Choose second alignment star If the Alignment State is Aligned then the Alignment Wizard is finished 4 2 Instrument Display interface 4 2 1 Instrument Display commands ATCL includes a sub set of functionality that exposes SkyWalker Instrument Display interface These are simply additional ATCL commands that allow Client software to implement an Instrument Display on their screen SkyWalker s Instrument Display interface is the only guaranteed fully implemented method to interface to all of SkyWalker s current features There will be fancy Client programs e g Maestro and even 3rd party running under various operating systems however there is no certainty that they will always fully support all of SkyWalker s features nor stay up to date with enhancements to SkyWalker firmware unless they implement an Instrument Display interface Clients can provide a dumb 8 line by 21 character display compatible with Astrometric Instrument s HP2 handpaddle with m
26. as Ham nw onae o Euren A eunte WR GetDomeDebug NEM QU CLR RN Returns an arbitrary string used for engineering debug purposes GetDomeSupplyVoltageAzimuth Returns 8 bit hexadecimal voltage sense ADC value Full range FF value represents 15 0v Any value below 1D indicates that the shutdown input to the azimuth module is active 36 Copyright Astrometric Instruments Inc GetDomeSupplyVoltageShutter HGvs HEX Returns 8 bit hexadecimal voltage sense ADC value Full range FF value represents 15 0v Any value below 1D indicates that the shutdown input to the azimuth module is active Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or ES Command name Description ee return SkyWalker s SwitchPro peripheral or SkyWalker model supporting UniDrive outputs or FocsPro accessory is required for the following commands to function NO 47S PF 8 0 j NO 7G MEE p mM poan J OAJ BECONDS AIAJ 0 hh lS pee NU oo T FocusFastOn m Pu or In Po Pu or In ih gt FocusSlowOn gt Ou or In pulse at focus FastRate for duration set with SetFocusPulseTime command Eo Out or In pulse at focus SlowRate for duration set with SetFocusPulseTime command Astrometric s FocusPro accessory is required for the following commands to function Note for FocusPro commands which expect a numeric parameter require that number be in hexadecim
27. ction of a communications error the Client should also refresh the Instrument Display the ID Refresh command since the errored and flushed packet may have been an Instrument Display update asynchronous response which if lost would leave the Instrument Display in a different state then SkyWalker s internal representation of the Instrument Display Note some CCD camera control software will disable the PC s interrupts This particularly drastic action can result in communications errors particularly Overrun errors since the PC s processor cannot always reliably service the serial communications hardware input buffer Note if SkyWalker seems unresponsive for any reason then it may be because it has suffered an InternalError i e SkyWalker software or hardware failure If this is the case then SkyWalker will respond with an internal error asynchronous message i e SkyWalker software or hardware failure All subsequent ATCL commands to SkyWalker will result in a repeat of the internal error asynchronous message The Client should cease sending commands following reception of an internal error and instruct the user to power cycle SkyWalker i e a power cycle is necessary to resume normal operation 2 10 5 Managing SkyWalker s presence The serial communications link between SkyWalker and the Client can be lost at anytime This can result in a partially formed reply to a command or asynchronous message i e the semicolon character has not completed
28. day number sD DD decimal number with indicated number of integer and fractional digits The range of acceptable values is detailed in command 6699 descriptions s is sign and if present is optional if the associated value is positive 6699 sNN NNN Integer number with comma 10 3 delineation The range of acceptable values is detailed in command descriptions s is sign and if present is optional if the associated value is positive VIEW VEL View Velocity in the format XX XX lt units gt where units can be deg sec amin sec asec sec or X VIEW ACCEL View Acceleration in the format XX XX units where units can be deg sec amin sec or asec sec where the subscript 2 can be represented by the hex character Ox1E or OxB2 SECONDS XXX XXXsec Note for purposes of timing events such as duration of High Drive assertion SkyWalker internal timing resolution is 0 075sec therefore the SECONDS value is rounded to the nearest 0 075sec increment by SkyWalker for these uses DEG XX Xxdeg represents an angle DEG PER SEC XX XXXXdeg sec TEMP temperature in the form XX XdegC or XX XdegF FLAG Yes or No SIGN Positive of Negative SIDE East West or Unspecified 3 2 3 Additional conventions Leading zeros in a parameter e g 072 34 44W for longitude are allowed but unnecessary Leading zeros are also possible in a retu
29. dit box field with xxxxx Rxxxxx Fill edit box field with xxxxx and provide units rolling button S Draw scroll up down and page up down buttons adjacent to the Instrument Display X Remove hide any Edit box page up down buttons or scroll up down buttons from the Client s screen i e SkyWalkeris done with them 4 2 3 The Instrument Display edit box To change settings or cause action general purpose data must often be provided to SkyWalker Examples include 12 23 45 for the RA coordinate of a GoTo 14 440 000 for the motor steps per rev or 72 43 23W for the site longitude ATCL provides one instrument display command and one asynchronous reply that allows the Client to enter edit general purpose data SkyWalker will send the Exxxxx or Rxxxxx asynchronous reply preceded by the ATCL_IDC_ASYNCH special character to the Client whenever it needs the Client to place an edit box on its Instrument Display The xxxxx field of this reply provides the default contents for the edit box The Client must provide a means for the user to change the edit box contents Once the user has finished with the edit box entry editing they would hit Enter The Client would then send the command ID EditBoxReturn with the semicolon terminated contents of the edit box to SkyWalker Servo Note although not strictly required it is recommended that the edit box be placed directly on the Instrument D
30. e Client sends an EnableSSCN QEcn command and disabled be default at SkyWalker power up and after the DisableSSCN QDcn command If enabled static status change notification works as follows when static status changes internal to SkyWalker an asynchronous message proceeded with the ATCL_CHANGE_NOTIFY special character is issued Following the special character is the 4 charater ATCL command that would have been used to get the changed status Following that is an equal sign and the string that SkyWalker would return if the 4 character command were issued directly For example if the encoder counts per rev in X was changed then the following change notification would be sent EGcx 45 000 Where is the preceding ATCL CHANGE NOTIFY special character EGcx is the GetEncoderCountsPerRevX command mnemonic and 45 000 is the new counts per revolution value The command reference section of this document notes all ATCL commands that are used to get static status for which this feature applies see note 1 This is a notifying command for SkyWalker s Static Status Change Notification feature Notes amp additional requirements It is required that the Client still does one run through its polling loop for all static status that it supports when starting up This is required rather than the idea that all change notifications fire after the EnableSSCN is received because the later would results in a flood of
31. e messages which are asynchronous to any command reply pair A special character that makes their identification possible always precedes messages 2 10 3 Start by getting out of ACL mode and checking SkyWalker s firmware version SkyWalker always powers up in ACL i e LX200 emulation mode This is necessary since Client software that is only LX200 compatible and not SkyWalker compatible may not send the ACL_ACK character before any other commands Therefore the first ATCL command that the Client software sends to SkyWalker should be the ATCL_ENTER single character command to be sure SkyWalker is ready to work in ATCL mode In fact the Client should continuously poll for SkyWalker s presence by sending the ATCL_ENTER single character command until an ATCL_ACK command is received Note this ATCL_ENTER polling should not be at too fast a rate to avoid SkyWalker input communications errors during power up A polling rate of once per second is nominal Next the Client application should query SkyWalker s firmware version This is an important next step since if SkyWalker is left inoperable e g after a malfunctioned firmware upgrade then it will reply with a version of 0 00 000 in response to the GetSkyWalkerFirmwareVersion HGfv command If SkyWalker reports a version of 0 00 000 then SkyWalker s firmware must be upgraded before it will function The Client should either a Proceed directly to upgrade SkyWalker s
32. ecimal A value of 124 po ges decimal is equivalent to 124 000 steps per second All other legal values scale linearly Copyright Astrometric Instruments Inc 35 SetDomeAccel HSda HEX Bounded to a hexadecimal value of 1 to FF FF hex is 255 decimal A value in the range of 1 to 255 A value of 255 decimal is equivalent to acceleration ramp to full speed i e 124 000 steps second in 1 8 seconds All other legal values scale to a ramp time inverse linearly smaller acceleration leads to larger ramp time in reverse linear manner GetDomeAccel BRA HEX o AC GetDomePosition er step position GetDomeAzMoveMode Left moving left Right moving right GoTo GetDomeShutterStatus Returns a character with the following possible values 0 for Opened 1 for Closed 2 for Opening 3 for Closing 4 for ShutterError 5 if the shutter module is not communicating to the azimuth module GetDomeLimits Returns five characters 12345 where each character can be 0 inactive or 1 active First character 1 UpperShutterOpened switch state Second character 2 UpperShutterClosed switch state Third character 3 LowerShutterOpened switch state Forth character 4 LowerShutterClosed switch state Fifth character 5 AtHome bit See DomeHome command Eri a a A E DomeAzGoTo Dgo HEX Accepts a signed 32 bit hexadecimal number esum Mee me SesesgsWe Ey oem Mx ue Seg tain br
33. emicolon terminated and are preceded with a special character that allows the Client to distinguish the message from SkyWalker return data Messages can occur at anytime except never in the middle of a command reply They can and often do occur between when the Client sends a command to SkyWalker and when the Client gets a reply back Because these messages can occur at anytime and are not necessarily associated with any ATCL command they are called asynchronous messages The Client must have logic to sort the asynchronous messages from command replies ATCL messages never exceed a length of 88 characters excluding the preceding special character and the terminating semicolon The Client s message display area if one is implemented should therefore have the ability to log messages up to 88 characters long In addition to displaying the message to the user it is recommended that the Client follow these guidelines Issue a sound for each message to alert the user An archive of standard sound wave files is provided at www astrometric com reasources sounds zip for this purpose ATCL STATUS Status wav ATCL WARNING Waming wav ATCL ALERT Alert wav ATCL INTERNAL ERROR Error wav There are a few special status messages that the Client may associate the following special sounds Accel wav Status GoTo commenced Status GoTo Anchor commenced Decel wav Status GoTo completed 8 Copyright Astrometric Inst
34. enu selection buttons and a back button and then with little overhead code expose SkyWalker s Instrument Display The engine behind the Instrument Display resides on SkyWalker and ATCL provides a set of commands that signal Instrument Display button presses to SkyWalker and provide for SkyWalker to write the contents of the Client hosted display In addition to the three return values possible with ordinary ATCL commands i e ATCL_ACK ATCL_NACK and an actual return string Instrument Display commands can return additional single special character responses The complete list of possible Instrument Display return values is Return string with semicolon termination character ATCL_ACK ATCL ID CMND a user initiated action was successfully completed The Client should issue a click sound ATCL ID LINK the user pressed a button that resulted in the display of a new Menu Page on the Instrument Display The Client should issue a new page sound ATCL ID DING the user pressed a button that does nothing The Client should issue a ding sound ATCL NACK Copyright Astrometric Instruments Inc In the table below shaded commands are generally used only by the Instrument Display on a handpaddle e g HP2 that has buttons to support the associated commands Command name Mne Parameter s Command description monic ID MenuButtonPressed IBpm Menu button A menu button was pressed ec 1 to rid ID Back IBbk None The Bac
35. er is silent at power up by default and will not issue the above messages SkyWalker comes out of silence after reception of the first ATCL command from the Client 2 9 Serial communications settings As mentioned in the Bandwidth and latency requirements sub section the baud rate requirements for ATCL are low and the overall performance is likely to be more a function of OS communications latency Therefore a fixed low rate of 19 200 baud has been chosen for SkyWalker s Client RS232 interface available from the connector labeled Comm on SkyWalker Note we have considered the possibility of allowing higher baud rates in the future however SkyWalker will always power up with its Client port configured for 19 200 baud ATCL may add commands in the future that would provide for baud rate change ATCL requires that the Client be setup for 8 bit data 1 stop bit with no parity checking enabled Copyright Astrometric Instruments Inc 2 10 Client software design implications With the ATCL protocol background information provided above it is worthwhile summarizing the implications on Client software design 2 10 1 Client commands must take turns Firstly the Client must not send new commands until it receives the full reply to a previous command This simplifies Client design since there is a lock step correspondence between commands and replies 2 10 2 Receive asynchronous messages The Client must have the ability to recetv
36. erial or Metric Returns Imperial or Metric Range is from 0 i e off to 8 i e max If at 8 then this command has no effect DecLED Brightness none Range is from 0 i e off to 8 i e max If atO then this command has no effect GetLED Brightness FGb N Range is from O i e off to 8 i e max ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature IncLED Brightness 3 7 GoTo commands Parameter or Description Command name return GoTo initiation GoToSelectedObject GOs knone gt If refraction correction is enabled then the object coordinates are adjusted for refraction GoToTargetRA Dec GTrd none The Epoch assumed for target RA Dec is set with the SetEpochOfEntry command If refraction correction is enabled then the target coordinates are adjusted for refraction GoToTargetRA DecEpochNow GTrn none The Epoch assumed for target RA Dec is EpochNow If refraction correction is enabled then the target coordinates are adjusted for refraction GoToTargetAltAz GTiz none Target coordinates are observed Alt Az and are not adjusted for atmospheric refraction GoToLast GoTo the coordinate of the last Goto GTop none GoTo the preset Park position Upon the completion of the GoTo the TrackRate is set to Drift and the AtPark flag is set The status of alignment is unaffected GoToPark t Parameter or Command name ee Descripti
37. errors etc are signaled through ATCL s asynchronous messaging scheme described in the sub section Asynchronous Messaging above Copyright Astrometric Instruments Inc 3 1 Command group list Command group Alignment and Calibration Coordinate query Axial Encoder specific General preferences GoTo settings initiation and status Hardware control and status Instrument Display Handpaddle and autoguider Time tools Motors and gearing Mount settings Object database Pointing model Administrative and overhead Tracking settings Sites settings Time and date User lists Mark and return Motion control and status Reserved for future use Command group character A C E F G H I K L M N O P Q R S T U V X B D J W Y Z Copyright Astrometric Instruments Inc 19 20 3 2 Command notes and conventions 3 2 1 Notes There are two basic types of ATCL commands Set and Get Set commands take one and only one parameter and Get commands return one and only one value ATCL syntax is designed so that command parameters are as atomic as possible That is to say that the parameters provide single values rather than multiple values For example commands such as SetTargetRA RA SetTargetDec Dec and GoToTargetRA Dec exist rather than GoToRA Dec RA Dec This is so that SkyWalker can test syntax at a more atomic level Command mnemonics ARE case sensitive Com
38. et aligned GetAxialRealX SIGNED 3DIGIT Returns SIGNED 3DIGIT REAL GetAxialRealY SIGNED 3DIGIT Returns SIGNED 3DIGIT REAL GetAxialVelocityX DEG PER SEC Returns DEG PER SEC 26 Copyright Astrometric Instruments Inc GetAxialVelocity Y CGvy DEG PER SEC Returns DEG PER SEC GetTargetAxialX SIGNED 3DIGIT Returns SIGNED 3DIGIT GetTargetAxialY CGty SIGNED 2DIGIT Returns SIGNED 2DIGIT GetScopeOrientation Returns Primary or Secondary or N A if not yet aligned SetCoordFormat CScf gt Determines format that coordinates are presented in see Formats section Choices are Standard or Precise GetCoordFormat Returns Standard or Precise GetAutomaticMoveStatus CGam FLAG Returns Yes if the telescope is automatically seeking a target e g GoTo Home Index Park otherwise No is returned Note after SkyWalker process a targeting command it can take up to 1 second before GetAutomaticMoveStatus returns Yes Note even for a failed targeting command this command will issue an SSCN This is so that the client can determine from SSCN if the targeting command failed as well as succeeded GetCoordinateAggregate1 CGa1 gt Returns present RA Dec Hour angle Az Alt Airmass and Refraction correction magnitude in the format HOURS SIGNED 2DIGIT IHOURS UNSIGNED 3DIGIT SIGNED 2DIGIT DD D DD DDamin GetCoordinateAggregate2 CGa2 gt Returns AutomaticMoveStatus ScopeOrientation AxialRealX AxialRealY Axial
39. feature Parameter or Command name Code return Description Timer LSto FLAG String Yes to turn on and No to turn off SkyWalker s Timer 3 e NN Gommern GROSS Gemere kd OURS GeTWmeWanngme kGw HOURS Sameer hse pe T GeTmeWanmEmbeiT kde pe O Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or Command name Code Description TimeStamp SetTimeStampNow SkyWalker sets TimeStamp to the value of TimeStamp1 and records the present time as TimeStamp1 GetTimeStamp1 LGt1 gt etuns XX gt HH MM SS where XX is Time Stamp Format UTC or Local 46 Copyright Astrometric Instruments Inc GetTimeStamp2 LGt2 Returns XX gt HH MM SS where XX is Time Stamp Format UTC or Local GetTimeStampDelta LGtd HOURS Returns the difference between TimeStamp1 and TimeStamp2 SetTimeStampFormat LStf gt UTC or Local GetTimeStampFormat LGtf Pe O O UTC or Local Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Time tools aggregate GetTimeToolAggregate LGta gt Returns AlarmRemaining TimerRemaining in the format hh mm ss hh mm ss Note the Client can use AlarmOn and TimerOn to determine if it is necessary to issue this aggregate 3 12 Motor and gearing commands Parameter or Command name Code return Description Motor settings SetMotorPolarityX MSpx SIGN String Positive or Negative
40. firmware to a valid version For information on ATCL commands to upgrade SkyWalker s firmware please contact Astrometric Instruments Inc Or b If the Client does not support firmware upgrade recommend that the user run Astrometric s SkyWalker Client Maestro or Astrometric s firmware upgrade utility SW_Firmup to upgrade the software Note SkyWalker will also reply with a version of 0 00 000 in response to the GetSkyWalkerFirmware Version HGfv command following use of the FlashInvalidate QFiv command 2 10 4 Properly handle error conditions Copyright Astrometric Instruments Inc 15 16 Typical PC serial communications hardware has a limited hardware input buffer that stores up incoming characters until the PC s operating system can find the time to un load the buffer If the PC s operating system is not fast enough in servicing the hardware input buffer then characters can be lost Specifically incoming characters from SkyWalker can cause a buffer overflow Therefore the Client must monitor the Overrun and Framing errors that the PC s UART provides If an error is detected then the Client should flush the communications buffers clear the error flags and re send the last un replied command if one exists and carry on This is a retry approach rather than a give up approach and is preferable from the user s perspective Error logging is recommended so that the user is aware of a bad interface Note upon dete
41. hGoToDirDec cial Poo String North or South specifying the direction in which the approach is made for Polar mount types GetConsistApproachGoToDirDec GGed p gt String North or South Copyright Astrometric Instruments Inc 31 SetConsistApproachGoToOffset GSco gt Arcminutes in the range 1 60 in the form 1 00amin 60 00amin Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature 3 8 Hardware commands Parameter An Command name Code ATIUM Description or return TCS devices GetSkyWalkerModel HGsm gt Returns a string indicating the SkyWalker model GetSkyWalkerFirmwareVersion HGfv m nn rrr Note if 0 00 000 is returned then SkyWalker s firmware is unprogrammed and it is necessary to proceed directly to SkyWalker s firmware upgrade procedure since SkyWalker will not accept commands other than firmware upgrade commands wwe warte Em UN e eS GetSkyWalkerFlashModel HG im gt Possible return strings IntelB3 4MB or IntelC3 4MB GetSkyWalkerSupplyVoltage H w gt In the format D Dvolts GetSkyWalkerSupplyVotlageStat Returns OK if supply voltage is above low voltage warning point Low if supply voltage is between low voltage warning point and under voltage fault point Under if supply voltage is under the under voltage fault point GetHP1 Present HGip GetHP2 Present GetHREMX Present GetAutoM
42. haracters are ignored Missing a semicolon termination character will eventually result in an ATCL_CMND_TIMEOUT error and SkyWalker will purge all characters received since the last from its input buffer There is one and only one exception to the above command format This is for the ATCL_ENTER command which is a one character command used to take SkyWalker out of ACL mode i e LX200 emulation mode It is one character so that SkyWalker can parse for it when in ACL mode Return strings are straight ASCII printable characters Semicolon terminated so the Client knows when the return string ends Once the semicolon character of a return string is received the Client is free to send another command Detailed ATCL command syntax is provided in the ATCL Syntax Reference section below Copyright Astrometric Instruments Inc 2 Advanced functionality 2 1 Asynchronous Messaging As mentioned above ATCL supports SkyWalker initiated asynchronous messages that can be sent to the Client at any time A unique non printable ASCH character i e ASCII character with bit7 set to 1 precedes all asynchronous messages This is so that they can be picked out of the normal stream of replies coming back to the Client ATCL s messaging feature provides important information to the Client that is not available in the normal Client command return value All messages that include a string i e some messages are only single character are s
43. he Managing SkyWalker s presence sub section above the Client should implement its own timeouts to detect communications problems with SkyWalker This is particularly important to prevent the Client from locking up in the event that communications with Sky Walker is lost while the Client awaits a reply Copyright Astrometric Instruments Inc 17 3 18 ATCL Command Reference The syntax of every ATCL command is simply gcccppp The is the required prefix character gecce is the command mnemonic which is always 4 characters where g is the command group character and ccc is unique within the command group ppp is 0 or more command parameters All command must be terminated with a i e semicolon character IT IS VERY IMPORTANT to remember to apply a semicolon character to the end of the command otherwise an ATCL CMND TIMEOUT error will result For every ATCL command SkyWalker returns something either actual data in the case of the Status commands for example or a special character indicating success or lack of success If the command was successful and return data is not involved then the single special character ATCL_ACK is returned for Instrument Display commands there are further special character success codes If the command was not successful then the single special character ATCL_ACK is returned Any errors resulting from the command e g syntax errors system alerts communications
44. ichever is slower in both axes HomeDiscovered and HomeSeekError are cleared if this command successfully starts the discovery operation HomeDiscovered is set if this command successfully completes the discovery operation and HomeSeekError is set if this command is unsuccessful Note this command requires that Automation Modules are in the system SetHomeDiscovered ndis Sets HomeDiscovered state to FLAG value Not recommended to use use HomeDiscover GetHomeDiscovered 9 Peg nna ale QNA FLAG SetHomelndexAxialX SIGNED 3DIGIT Sets AxialX coordinate of Home Index Not recommended to use use HomeDiscover EODD NN AShy SIGNED 2DIGIT Sets AxialY coordinate of Home Index Not recommended to use use HomeDiscover GetHomeSeekError AGhe FLAG See HomeDiscover and HomeSeek commanas Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or m Command name Code Nein Description Copyright Astrometric Instruments Inc 25 Align from Home Index HomeSeek none Initiates a sequence to find the Home Index in each telescope axis When the Home Indexes are found in both axes the AtHome flag is set accessible via the GetAtHome command the Track Rate is set to Drift to preserve an eventual AtHome condition and any alignment is voided The direction that SkyWalker moves to find the Home Index is specified by the SetHomelndexX DiscoverDir and
45. if there is a verify active incase the ATCL VERIFY special character is missed Two commands provide for this GetATCL VerifyActive QGva Returns Yes or No GetATCL_VerifyString QGvs Returns the last verification string sent to the Client which was proceeded by the ATCL VERIFY special character 2 7 Error protection Overrun and Framing error checking should be enabled at the Clients UART SkyWalker performs both of these error checks and issues ATCL FRAMING and ATCL COMM OVERRUN as necessary SkyWalker provides syntax error checking on all ATCL commands and issues an ATCL SYNTAX ERROR if there was an error SkyWalker provides timeout checks to guard against partially formed commands and to halt SkyWalker s sending of Asynchronous messages to an inactive Client Refer to the next section for complete details 2 8 Timeouts SkyWalker s Client interface when working in ATCL mode provides three types of timeouts 2 8 1 Command timeout Copyright Astrometric Instruments Inc 13 14 1 1 A command timeout occurs if more than 1 second transpires between the reception of a prefix character and the command completion character The command timeout protects against mis sequenced commands if communications with the Client software is lost i e potentially leaving a partially formed ATCL command In the event of a command timeout the ATCL CMND TIMEOUT single character Asynchronous Message i
46. isplay area of the Client s console window When an edit box is active SkyWalker may also have other Instrument Display fields active at a minimum field 0 contains the title of the current Display Page Therefore this specification sets the requirement that the edit box does not obscure the first 5 lines of the Instrument Display SkyWalker will restrict its simultaneous use of the Instrument Display when an edit box is active to fields 0 4 4 3 ATCL support from ASCOM Astrometric Instrument s Maestro ATCL Client software is ASCOM compliant In addition to support for the majority of ASCOM Telescope Server Interface Methods routines Maestro also provides support for an ASCOM Client to pass ATCL commands directly to SkyWalker This support is implemented through the CommandString ASCOM method To pass an ATCL command directly to SkyWalker call the CommandString method with a string parameter that is an ATCL command The response string of the CommandString function is the response from SkyWalker For example to set SkyWalker s ViewVel4 to 0 8deg sec you could use the following VBA CommandString code Set Scope CreateObject Maestro Telescope Response Scope CommandString KSv40 8deg sec Copyright Astrometric Instruments Inc
47. itten in Microsoft Visual Basic 4 Copyright Astrometric Instruments Inc ATCL also provides commands that provide exposure to SkyWalker Instrument Display interface These commands are implemented simply as additional ATCL commands that allow Client software to implement an nstrument Display on screen Astrometric Instruments Inc maintains ATCL documentation and Maestro Lite source code and documentation at www astrometric com support resources ATCL html Finally SkyWalker also supports a subset of the Meade LX200 variant of the ACL Astronomical Control Language Interface to SkyWalker through its Client interface i e Com port can be via ATCL or ACL Document conventions Astrometric specific terms are italicized and definitions for each are provided in the Glossary of terms section at the end of this document Related documentation This document refers to SkyWalker specific features and terms The SkyWaker User s Manual describes these features and defines the terms in detail Therefore it is strongly recommended that the SkyWaker User s Manual is read prior to this document SkyWalker s Client Interface SkyWalker s Client interface provides three means of accessing SkyWalker through serial communications 1 ATCL the Astrometric Telescope Control Language a general purpose open standard means of controlling polling SkyWalker 2 The Instrument Display sub set of ATCL commands provides a means for a small and si
48. k button was pressed ID Refresh IRfr None Request that SkyWalker redraw the ID ID JumpMenuPage IJmp toa 0 to Jump to menu page number ID_CursorUp IBcu None Move the cursor selection up one ID CursorDown IBcd None Move the cursor selection down one ID CursorPageUp IBpu None Move the cursor selection up one page ID CursorPageDown IBpd None Move the cursor selection down one page Copyright Astrometric Instruments Inc 55 ID GetNextMapltem IGmi None Get next item for a tree view Display Map The return value is Nnnnnnllxxxxxx Encoding is as follows Record Map item nnnnn at indent level ll as xxxxxx where nnnnn is the item number 00001 through 99999 Item number is incremented with sequential IGmi commands until there are no more items left at which point the IGmi command return value is Lnnnnn where nnnnn indicates the last item number that SkyWalker provided 11 is the indent level from 00 through 99 00 implies no indent xxxxxx is the NULL terminated title of the map item i e the Menu Page title Example assuming 300 items have already been processed then Main 1 Child m1 1 Child m1 2 Main2 Child m2 1 Child m2 1 1 would be encoded as return values to sequential IGmi commands as follows N0030100Mainl N0030201Child ml 1 N0030301 Child m1 2 N0030400Main2 N0030501Child m2 1 N0030602Child m2 1 1 If that were the end of SkyWa
49. list of available names depends on Meridian Avoidance i e Full Lower or None If using Full Meridian Avoidance use this command GetAlignmentStartingPositionFull AGp See SkyWalker User s Manual for a list of Starting Position names 22 Copyright Astrometric Instruments Inc SetAlignmentStartingPositionNonFull ASpn See SkyWalker User s Manual for a list of Starting Position names Note the list available names depends on Meridian Avoidance i e Full Lower or None If not using Full Meridian Avoidance use this command GetAlignmentStartingPositionNonFull AGgpn See SkyWalker User s Manual for a list of Starting Position names AlignFromStartingPosition AFsp lt none gt Performs a Preliminary alignment from the currently defined starting position AlignFromTargetRA Dec none Marks an alignment sighting from pre set target using SetTarget commands RA Dec If Meridian Avoidance is Full and Alignment Side has not been chosen with SetAlignmentSide command then a warning message will result and the alignment will fail When using this command it IS necessary to use the SetAlignmentSide command first Note target RA Dec are assumed to be valid in the EpochOfEntry use SetEpochOfEntry command AlignFromTargetRA DecEpochNow none Same as AlignFromTargetRA Dec except that target RA Dec are assumed to be valid for an Epoch of Now AlignFromTargetRA DecCalcSide none Marks an alignment sighting from
50. lker s list then L00306 would be returned in response to subsequent IGmi commands See Note for additional suggestion Copyright Astrometric Instruments Inc At power up SkyWalker resets its map item ID_ResetMapSequence ID_GetSelectedMapItem Retrieves the map item number for the Menu ID_EditBoxReturn Returns the string currently in the Edit box to ID_EditBoxRoll Note 1 when using the ID GetNextMapltem command the Client will receive a complete list of all Menu Page titles that are not hidden Hidden Menu Pages exist and cannot be displayed on the Display Map since they don t link from just one parent Menu Page It is suggested that if the Client receives a Menu Page number using the ID GetSelectedMapItem command that was not part of the list acquired with the ID GetNextMapltem command i e that is a hidden page that the proper IGsi IEbr None None Edit box contents Edit box contents counter The Client can reset it as well with the ID ResetMapSequence command This command should be used if the Client detects a communications fault page that SkyWalker s Instrument Display is currently displaying SkyWalker Returns the string currently in the Edit box to SkyWalker SkyWalker then rolls the display units and re issues the Edit box contents to the Client via the E Instrument Display asynchronous response next section course of action is simply to display the
51. ly A command was only partially formed within SkyWalker s command timeout period 1 second See Instrument Display interface section below See Instrument Display interface section below See Instrument Display interface section below See Static Status Change Notification Section below Copyright Astrometric Instruments Inc 0x06 ACT ACK A special character used in LX200 lingo Use of this character is specifically avoided in the ATCL protocol and will immediately result in SkyWalker switching into ACL mode The Client must send a single character ATCL ENTER command to leave ACL mode and re enter ATCL mode 1 These are special characters so that they are single character errors i e they have no associated string just a semicolon termination character and hence have the best chance of being successfully communicated from SkyWalker to the Client 2 ATCL_NACK essentially means that the command will not be executed as the Client intended There are several possible reasons for this Invalid command mnemonic Valid command mnemonic but parameter error e g syntax error or out off range etc e Valid command and valid parameter but illegal operation given present SkyWalker state e g GoTo if not yet aligned e Valid command and valid parameter but the command was out of sequence generally only possible with the firmware upgrade commands which must rigidly follow a specified sequence In all cases an asynchronou
52. mand parameters are NOT case sensitive 3 2 2 Conventions Conventions for formats specified in the Parameters or return column are interpreted as SIGNED 2DIGIT For CoordFormat Precise sDD MM SS within range 90 00 00 to 90 00 00 For CoordFormat Standard sDD MM within range 90 00 to 90 00 SIGNED 3DIGIT For CoordFormat Precise sDDD MM5 amp SS within range 180 00 00 to 180 00 00 For CoordFormat Standard SDDD MM within range 180 00 to 180 00 UNSIGNED_3DIGIT For CoordFormat Precise DDD MM SS within range 000 00 00 to 360 00 00 For CoordFormat Standard DDD MM within range 000 00 to 360 00 HOURS For CoordFormat Precise HH MM SS within range 00 00 00 0 to 24 00 00 0 For CoordFormat Standard HH MM within range 00 00 to 24 00 Copyright Astrometric Instruments Inc 9 9 9 o LATITUDE in the form DD MM SSh where h is hemisphere i e N or S Within the range 90 00 00N to 90 00 00S LONGITUDE in the form DDD MM amp SSh where h is hemisphere i e E or W Within the range 180 00 00W to 180 00 00E TIMEZONE HH MMh where h is hemisphere i e E or W Within the range 13 00W to 13 00W Note there are some South Pacific islands near the international dateline that actually use 13 00E e g Nuku alofa Tonga Additionally 0 00 is acceptable for GMT i e no hemisphere designation necessary SHORT TIME HH MM SS LONG TIME DDD HH MM SS where DDD is
53. me to 18 000sec Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or Command name Code retum Description oome ae peos pese eae 0000000 posom pe BECO LLL NNNM DU NN RN Owens e p pua 0000 Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Dew Heater Parameter or Command name Code Description Copyright Astrometric Instruments Inc 39 SetDewHeaterl Enabled HSe1 FLAG String Yes to enable and No to disable SetDewHeater2 Enabled HSe2 FLAG GetDewHeater2 Enabled HGe2 FLAG SetDewHeater3 Enabled HSe3 FLAG GetDewHeater3 Enabled HGe3 FLAG SetDewHeater1_OnTime HSo SECONDS 0 075sec to DewHeater1 Period SetDewHeater2 OnTime HSo2 SECONDS 0 075sec to DewHeater2 Period SetDewHeater3 OnTime HSo3 SECONDS 0 075sec to DewHeater3 Period SetDewHeater1 Period HSP SECONDS DewHeater1_OnTime to 18 000sec SetDewHeater2 Period HSp2 SECONDS DewHeater2 OnTime to 18 000sec SetDewHeater3 Period HSp3 SECONDS DewHeater3 OnTime to 18 000sec Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or mE Command name Code Stun Description Momentary SetMomentary1_ Enabled HSmt FLAG String Yes to set Momentary output and No to clear SetMomentary2_Enabled HSm2 FLAG String Yes to set Momentary output and No to clear SetMomentary3 Enabled HSm
54. mple instrument display screen with minimal buttons to interface to SkyWalker Primarily this is used to create an HP2 emulator in Client software 3 ACL the Astronomical Control Language The command syntax for ACL commands supported by SkyWalker is Meade LX200 compatible SkyWalker supports a large subset of the LX200 protocol as described in the SkyWalker User s Manual The ACL protocol is not full reply ATCL is full reply as described in the next section and therefore Client software cannot intermingle ACL commands with ATCL commands If SkyWalker detects ACL via an ACL ACK character on its Client port it will immediately enter ACL mode In ACL mode SkyWalker simply emulates a Meade LX200 To get SkyWalker out of ACL mode and into ATCL mode the Client must send a single ATCL ENTER special character defined below and successfully receive back an ATCL_ACK special character from SkyWalker Note no further treatment of ACL is provided in this document See the SkyWalker s User s Manual for full details Copyright Astrometric Instruments Inc 1 Basic functional overview 1 1 Protocol Introduction All ATCL commands have a return value indicating success failure or returning requested data There are no commands that do not provide at least a simple success fail return value All Client applications should behave within the bounds of this full reply protocol This is to say that a Client should send a command and
55. nable and No to disable action when Axial Limits are struck for the X axis LA SetAxialLimitUpEnabled HSeu FLAG String Yes to enable and No to disable action when the Up Axial Limit is struck Sc M SetAxialLimitDownEnabled HSed FLAG lt String Yes to enable and No to disable action when the Down Axial Limit is struck wastes Me Rug 0 Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or Command name Code ETUR Description SkyWalker s SwitchPro peripheral or SkyWalker model supporting UniDrive outputs or DomePro accessory is required for the following commands to function GetDomePolarity DomeRightOn lt none gt Causes azimuth slewing motion right i e increase in azimuth lt none gt Kill dome azimuth motion Astrometric s DomePro accessory is required for the following commands to function Note for DomePro commands which expect a numeric parameter require that number be in hexidecimal format DomePro does not directly accept decimal values KillDomeAzimuthMovement DomeLeftOn HDlo nne Causes azimuth slewing motion left i e decrease in azimuth Counts per revolution of the dome in azimuth Hexadecimal value in the range 20 32 to 40000000 1 073 741 824 and must be an even number Pla i No JMX oq Sani ERR Bounded to a hexadecimal value of 1 to 7C 7C hex is 124 d
56. nce after the first sighting has been made 2 Use the GetAlignmentStartingPosition command to determine what Starting Position is currently selected for use in SkyWalker 3 If Meridian Avoidance is Full found via the GetMeridianAvoidMethod command and Starting Position is None then Provide a screen with suggested title Choose side of sky that allows the user to select between In the East or In the West for Alignment Side Include instructive text e g In which side of the sky will alignment commence Send the SetAlignmentSide command to SkyWalker with a parameter dependent on the user selection i e East or West Otherwise it is unnecessary to prompt for the side of the sky that alignment will commence see next step 52 Copyright Astrometric Instruments Inc If Starting Position is None regardless of Meridian Avoidance then skip to step 6 Otherwise provide a screen with suggested title Choose starting position with a scrollable list of Starting Positions with the currently selected one as the default selection Include instructive text e g Please verify that the telescope orientation is If the user selects a different Starting Position then send a SetAlignmentStartingPositionFull or SetAlignmentStartingPositionNonFull command to SkyWalker to choose the new Starting Position Note if the user selects None for a Starting Position and Meridian Avoidance is Full then it
57. nd was not successful either because of communications error or syntax error In this case the single special character ATCL NACK is returned In addition to replies and return data from Client initiated ATCL commands ATCL also supports SkyWalker initiated asynchronous messages that may be sent to the Client at any time These messages include SkyWalker s Status Warnings Alerts and Errors but can also include other data such as text update for the Client s Instrument Display reporting of command syntax errors in more detail than the ATCL_NACK return value provides or communications errors 1 2 ATCL Command Syntax introduced ep ATCL command syntax follows the form nnnnpppp where the quotation marks are not part of the command is the prefix character nnnn is the four character command mnemonic pppp is the character parameter string not all commands take parameters and a 5 i e semicolon character always completes the command 6 Copyright Astrometric Instruments Inc An example ATCL command is the SetTargetRA command which is used prior to a GoTo Alignment or Calibration to set SkyWalker s internal Right Ascension target buffer An example SetTargetRA command in its entirety appears as follows NES Urs 34 567 J UMA N Prefix character Semicolon Command RA Coordinate are termination mnemonic parameter Multiple will cause an ATCL CMND OVERRUN error Multiple semicolon termination c
58. ns Go Mine nee COGNO Nee dicta a ww NN NNN ro Te recon e aon e of Ticks 75 milliseconds between application of corrections EELEE T NN NNN The maximum number of encoder counts of absolute error between encoder position and motor position This value is cleared a each time this command is called and b when Axial Encoder Track Lock is not enabled GetAxialEncoderTrackLockErrorY The maximum number of encoder counts of absolute error between encoder position and motor position This value is cleared a each time this command is called and b when Axial Encoder Track Lock is not enabled Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or Command name Code return Description Encoder diagnostics GetEncDiagPositionX NN NNN Returns an integer indicating the number of encoder counts detected since the last ZeroEncDiagPositionX command ZeroEncDiagPositionX EZex nne Zeros EncDiagPositionX count GetEncDiagPositionY EGey NN NNN Returns an integer indicating the number of encoder counts detected since the last ZeroEncDiagPositionY command ZeroEncDiagPositionY Zeros EncDiagPositionY count ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature 3 6 Preference commands Parameter or Command name Code retum Description Copyright Astrometric Instruments Inc GoTo initiation SetUnitsFormat GetUnitsFormat FGu Imp
59. odX Auxln Returns Yes if X RA Az Automation Module Auxln input is active high and No if inactive and N A if Automation Module X is not present in the system GetAutoModY Auxln i Returns Yes if Y Dec Alt Automation Module Auxln input is active high and No if inactive and N A if Automation Module Y is not present in the system SetAutoModX AuxOutEnabled HSox FLAG String Yes to enable and No to disable the Automation Module s AuxOut output 32 Copyright Astrometric Instruments Inc GetAutoModX AuxOutEnabled HGox gt Yes No or N A where N A indicates that the Automation Module is not installed in the system SetAutoModY AuxOutEnabled FLAG String Yes to enable and No to disable the Automation Module s AuxOut output GetAutoModY_AuxOutEnabled Yes No or N A where N A indicates that the Automation Module is not installed in the system ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or T Command name Code dam Description Fault status and control GetTopActiveFault Returns a string representing the highest priority i e top active fault None if no faults are presently active Possible faults and return strings in priority order are HardLimitRA HardLimitDec UnderVoltage StallRA StallDec DrvOverTempRA DrvOverTempDec MotOverTempRA MotOverTempDec
60. on i return GoTo restrictions SetGoToHorizon GSgh DEG Sets the minimum altitude allowed for GoTo targets Allowable range is 0 0deg to 45 0deg 30 Copyright Astrometric Instruments Inc SetGoToOrientation GSgo gt Primary Secondary Current or Fastest Not available for Full Meridian avoidance or when the Up Soft Limit is used GetGoToOrientation GGgo h gt Primary Secondary Current or Fastest Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or P Command name Description ee CN B return GoTo status GetGoToRemainPercent GGgr 100v to 0 GetGoToProgressPercent GGgp h gt 0 to 100 GetNumberOfGoTos GGgn NN NNN Returns number string reporting number of GoTos since power on Parameter or TM Command name Code deM f Description AutoCalibration exuti qe uc pasWesmussbss are wad wae ELI MM NM MN NN Sanaecabennd Sd PEG pesWemsmuncsaeewugsvsoANOSNWETWRE 000 EL pe p NN Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or Command name Code TBI Description GoTo restrictions SetConsistApproachGoToEnabled GSca FLAG String Yes to enable and No to disable Consistent Approach GoTo GetConsistApproachGoToEnabled GGca FLAG Returns Yes if Consistent Approach GoTo is enabled and No if disabled SetConsistApproac
61. outgoing SkyWalker communications that would likely overflow Client input buffers and complicate SkyWalkers output communications mechanisms Itis suggested that the Client runs its static status polling loop slowly in the background to catch any notifications that might have been missed Copyright Astrometric Instruments Inc It is suggested that Maestro issues the EnableSSCN command whenever it reconnects with SkyWalker after the connection with SkyWalker has been registered as lost This will prevent the problem where SkyWalker if powered down would disable static status change notification without Maestro knowing it 2 5 Status Aggregates Need description here 2 6 ATCL Verify Occasionally it is necessary to provide a verification dialogue between the user and SkyWalker For example it may be necessary for SkyWalker to ask the user how to proceed in certain instances To accommodate this dialogue ATCL provides a verify feature With this feature SkyWalker will send an ATCL VERIFY special character to the client followed by a question verify string When the client receives the ATL VERIFY special character it should present the string to the user in a dialog box with an OK and Cancel button If the user presses OK then send the ATCL_VerifyOK QAvo command to SkyWalker otherwise send the ATCL_VerifyCancel QAvc command to SkyWalker Note ATCL VERIFY is a convenience however the Client should continuously poll to see
62. powered down Note a successful previous alignment is necessary even though SkyWalker might have been powered down in the mean time AlignVoid Voids alignment returns alignment state to NotAligned Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Copyright Astrometric Instruments Inc 23 Parameter or s as Command name Code CT eil Description Calibration CalFromTargetAltAz ACIz none If refraction correction is enabled then the target coordinates are adjusted for refraction and are thus treated as apparent coordinates If refraction correction is disabled then the target coordinates are not adjusted for refraction and are thus treaded as observed coordinates CalFromTargetRA Dec ACrd lt none gt The Epoch assumed for target RA Dec is set with the SetEpochOfEntry command If refraction correction is enabled then the target coordinates are adjusted for refraction CalFromTargetRA_DecEpochNow ACrn lt none gt The Epoch assumed for target RA Dec is EpochNow If refraction correction is enabled then the target coordinates are adjusted for refraction fearromiasote AC eme 0000000000000 Parameter or Command name Code retum Description Park position MarkParkPosition lt none gt Marks the current Axial coordinates as the Park position Park position is stored in SkyWalker s nonvolatile memory GetAtPark lt none gt If the telescope has not moved since
63. pre set target RA Dec If Meridian Avoidance is Full then the proper Alignment Side is calculated by SkyWalker i e it is not necessary to use the SetAlignmentSide command If the target RA Dec fall outside of the Meridian limits or in an overlap zone accessible from either Alignment Side then a warning message will result and the alignment will fail Note target RA Dec are assumed to be valid in the EpochOfEntry use SetEpochOfEntry command AlignFromTargetRA DecCalcSideEpochNow none Same as AlignFromTargetRA DecCalcSide except that target RA Dec are assumed to be valid for an Epoch of Now AlignFromTargetAltAz lt none gt Marks an alignment sighting from pre set target using SetTarget commands Alt Az If Meridian Avoidance is Full and Alignment Side has not been chosen with SetAlignmentSide command then a warning message will result and the alignment will fail When using this command it IS necessary to use the SetAlignmentSide command first AlignFromSelectedObject none Marks an alignment sighting using the coordinates of the selected object Other details are identical as for the AlignFromTargetRA Dec command AlignFromSelectedObjectCalcSide none Marks an alignment sighting using the coordinates of the selected object Other details are identical as for the AlignFromTargetRA DecCalcSide command AlignFromLastPosition none Aligns from the Axial Coordinates which persist from the last alignment even if SkyWalker was
64. re Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or a Command name Code errr Description 44 Copyright Astrometric Instruments Inc Parameter or c Command name Code UT eR C Description QuickKeys Saoumo Ksa etae OOO Ge OK Funcion Kos eeo 00000 SeQudKeFuxdon Ksa setas T Ge uae Funcion Kam etes OOOO SOLL NNNM M NN NR Goues Funcion Kos foes SeQusKedFukn KS etae OOO OOO Ge QdKe Funcion Kos etes SetQuekKey7Funcion Ksar metes O OOOO GeiauciKey7 Funcion Koar setae J OO Eeue Ke j gt RRR For the above commands the CalFromEnc CalFromLastGoTo DriftToggle FocusPulseToggle GoToAnchor GoToLast GoToPark Hunt following assignment parameters InvertToggle Mark MarkReturn MirrorToggle Momentary1 Momentary2 Momentary3 Nothing OneShot apply Return TimeStamp Toggle1 Toggle2 Toggle3 or Wobble Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature 3 11 Time tools Parameter or m Command name Code T TNR Description SetAlarmOn LSao FLAG String Yes to turn on and No to turn off SkyWalker s Alarm Copyright Astrometric Instruments Inc 45 GetAlarmRemaining LGar HOURS Geaen Ge Hos OOS 0 T GmMamWammjnme Gm HOURS GmMamWammEmbedT Ge Fu T Indicates command supported Fo Te Static Status Change Notification SSCN
65. re P RENS Puget ead eee etes 4 2 3 The Instrument Display edit box sce ette etie EO Rte e de coe EE Ree Rete Eee cab doeet rte edem rre e er hee 4 3 ATC support from ASCOM ceat RUE APER RU eR RE Mei nee oii See Version For SkyWalker version 0 90 000 or later firmware For pre 1 00 000 firmware this specification is subject to drastic erratic oscillatory and un announced change Preface Astrometric Instrument s next generation telescope control system referred to as Astrometric Telescope Control System version 4 or ATCS4 moves the system s motion control intelligence from PC based software ie SkyGuide into hardware based firmware either inside new SkyWalkers or inside the S Box peripheral which enables ATCS4 functionality for older dumb SkyWalkers To complete the telescope control system a user interface to the intelligence within SkyWalker is required Astrometric Instruments provides a PC based Client program that provides one possible user interface to SkyWalker This Client program is called Maestro Maestro is not required to operate SkyWalker SkyWalker can also be operated stand alone i e without an attached PC with one of two handpaddle models as user interface HP or HP2 HPI is a basic handpaddle that provides keyed motion change of View Velocity change of Track rate Focus Dome control and access to 3 Quick keys HP2 provides all the features of HP in addition to an 8 line display and full ke
66. rn coordinate from SkyWalker Positive signed values e g 12degC can be sent either with or without a preceding character Copyright Astrometric Instruments Inc 21 A space character can be substituted for the colon character in all coordinate formats A comma character can be substituted for a decimal character European convention 3 3 Alignment and Calibration commands Parameter or Command name Code retum Description Alignment status commands GetAlignmentState pel Returns NotAligned Preliminary or Complete ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature Parameter or ee Command name Code Tum Str amp Description Alignment settings CheckSiteTimeDateSetOnce FLAG Checks if SkyWalker s site settings time and date have been set at least once This is useful during the alignment sequence to screen for the common error of the user not setting site time and date prior to first alignment Returns Yes if site time and date have each been set at least once and No otherwise This command also prompts an ATCL WARNING detailing which settings have not been made SetAlignmentSide v or West Specifies for Meridian Avoidance of FULL which side of the sky the subsequent _ e NAA will be completed on GetAlignmentSide n SIDE SetAlignmentStartingPositionFull See nM User s Manual for a list of Starting Position names Note the
67. ruments Inc Status GoTo Anchor completed Provide a message list where the text of each message is buffered and provided for display to the user Provide a pop up message for Warnings Alerts and Errors No pop up is suggested for Status 2 2 Special characters Special characters are used in the ATCL protocol as command return values indicating the success failure of a command and as a preamble characters preceding every ATCL asynchronous message Special characters are simply an ASCII character with bit7 set to 1 The Client can distinguish the start of an asynchronous message from ordinary replies and return data by parsing for the requisite special character that precedes each asynchronous message from SkyWalker Complete list of special characters Value Macro Description OxB1 ATCT ENTER 1 character command that instructs Sky Walker to immediately exit ACL mode and enter ATCL mode This should be the first command sent to SkyWalker when the Client starts up Ox8F ATCL_ACK Acknowledge received from SkyWalker when a command was successful and no return reply string results from the command 0xA5 ATCL_NACK 2 Returned when the command was unsuccessful An asynchronous message explaining the lake of success should occur 0x9A ATCL_STATUS Character preceding a status asynchronous message 0x9B ATCL_ WARNING Character preceding a warning asynchronous message 0x9C ATCL_ALERT Character preceding an alert asynchronous message
68. s issued and SkyWalker s command input buffer is purged Command timeouts are by default enabled at SkyWalker power up however they can be disabled at anytime with the DisableCommandTimeOut command and re enabled with the EnableCommandTimeOut command 2 8 2 Client update timeout It is desirable that SkyWalker issues no Asynchronous Messages if there is no Client connected to SkyWalker The impetus for this behavior is two fold 1 PC based communications hardware can suffer buffer overflow and subsequent dire consequences if there is no Client software to service the serial port connected to SkyWalker particularly a problem on some low cost USB to RS232 converters and 2 the communications DLL available as an interface between the Client and the SkyWalker demo program has a finite depth to its output buffer which will overflow with continuous update if there is no Client to unload it regularly To detect the presence or absence of a Client SkyWalker includes a client update timeout A client update timeout will occur if no ATCL command has been received within 5 seconds A client update timeout is silent i e there is no Asynchronous Message sent to the Client indicating that the timeout occurred however after a timeout occurs SkyWalker will not issue the following Asynchronous Message to the Client until a ATCL command is received from the Client ATCL_STATUS ATCL_WARNING ATCL_IDC_ASYNCH ATCL_CHANGE_NOTIFY 9 o Note SkyWalk
69. s message will be issued that provides more information So in short ATCL_NACK means that SkyWalker could not act upon the command for one of the reasons listed above Note it is possible to send a command for which SkyWalker replies with ATCL_ACK that does not successfully complete the commanded action The reason is that SkyWalker may execute the command after checking it for validity but encounter a reason later why the command can not be successfully completed In this case an asynchronous message will be issued providing details on the operations failure 2 3 Bandwidth and latency requirements For certain ATCL Client applications Maestro being an example the refresh rate of status on the Client s screen is difficult to support without special provisions in the ATCL syntax For example it is estimated that the Maestro Status Console Tab requires that approximately 25 ATCL status commands be issued on a regular interval interval of 1 second Given the full reply requirement of ATCL this would imply that 25 ATCL commands reply string pairs transpire in one second While a very small bandwidth is necessary to accomplish this est 400 characters sec easily accomplished with even a 9 600 baud connection the sum of the PC s operating system latencies responding to these 25 transactions would likely vastly exceed one second based on work with Windows Ring 3 response time done at Astrometric Instruments Inc Therefore there should
70. sitionX Motor Diag PositionY Motor VelX Motor VelY Motor LoadX Motor LoadY in the format XXXXXX XXXXXX XXsteps sec XXsteps sec XXX XXX GetPEC_BacklashStatAggregate Returns PECorrAppliedX PECorrAppliedY BLashAppliedX BLashAppliedY in the format XXXXsteps XXXXsteps XXXXsteps XXXXsteps GetGearStatAggregateX Retums Gear CountX Gear Index ToggleX Gear Index Gate StateX Gear Index Hysteresis CountX and Gear Index Since PowerUpX in the format XXXXsteps FLAG FLAG XXXXsteps FLAG Indicates command supported through SkyWalker s Static Status Change Notification SSCN feature For the remainder of the command reference see SW Client txt Copyright Astrometric Instruments Inc 51 4 Special topics 4 1 Client s Alignment Wizard It is recommended that the process of alignment be accommodated in Client software through the use of an alignment wizard Possible logic for this alignment wizard is described here Note this logic is recommended because it is consistent with the logic used in SkyWalker s Instrument Display interface Step Client action 1 User clicks the Align from Star s button Pop up the Alignment Wizard dialog box It is recommended that the CheckSiteTimeDateSetOnce command be used at this point to verify that SkyWalker s site settings time and date have been set at least once This will avoid the inconvenience of the alignment being prohibited if site time and date have not each been set at least o
71. successful completion of the last GoToPark command then returns Yes otherwise returns No Saanavanstaus LAS FLAG Notrocormendedto use use MarkParPostion GerPanttansiaws RGM TAG SeiParPostionava ASpe SIGNED_ADIGIT_ Notresommendedto use useManPamPoson GerParPositonaak A amp px SIGNED ODT O eeano A y s ndicates command supported through SkyWalker s Static Status Change Notification SSCN feature 24 Copyright Astrometric Instruments Inc Parameter or s as Command name Code CT eH a Description Home Index setup SetHomelndexX DiscoverDir SIGN Positive motion in X is towards the left when looking away from the Scope Pole HomeDiscovered is cleared if this value is changed SetHomelndexY DiscoverDir ASdy SIGN Positive motion in Y is towards the Scope Pole HomebDiscovered is cleared if this value is changed HomebDiscover none Initiates a sequence to discover the Home Index in each telescope axis When a Home Index is found its exact Axial coordinates are saved and available later for the HomeSeek command This command is not available unless SkyWalker is aligned The direction that SkyWalker moves to discover the Home Index is specified by the SetHomelndexX DiscoverDir and SetHomelndexY DiscoverDir commands When HomeDiscover is run the telescope needs to be far enough away from the Home Index switches that the telescope has fully accelerated to 1 0deg sec or VelMax wh
72. ypad that provides the entire functionality of SkyWalker s Instrument Display interface The Instrument Display interface provides a hierarchical menu based interface to nearly all of SkyWalker s features Astrometric Instruments SkyWalker client Maestro exposes SkyWalker s Instrument Display interface and provides a full Microsoft Windows based graphical user interface to SkyWalker For those familiar with Astrometric s older SkyGuide software these two components of Maestro are similar to SkyGuide s Instrument Display and SkyGuide s Console Tabs GUI interface i e Objects Status Actions and Settings tabs among others Maestro communicates to SkyWalker via the Astrometric Telescope Control Language ATCL ATCL is typically communicated over serial link e g RS232 or USB to SkyWalker s Client interface port labeled Com ATCL provides a very rich syntax for telescope control Astrometric Instruments Inc encourages independent software developers to provide an ATCL interface to their software ATCL is an open language There are no proprietary syntax or commands that are hidden from this standard All the information necessary to use ATCL is provided in this document In fact Astrometric Instruments Inc provides an example SkyWalker Client application Maestro Lite which is a stripped down version of Maestro to serve as a working example for independent software developers wishing to implement ATCL in their software Maestro Lite is wr

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