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LX200 Classic Command Set

Intended for professional programmers, the LX200 Command Set is used to write custom software for remote operation of the telescope with a personal computer. Each command is listed in a section appropriate to its type. Each entry in the command list includes the command name and any parameters which must be appended, any values which might be returned and a description of the command. The parameters and the return data are shown in a manner that indicates their format.  These formats are
listed below along with examples of how the data might actually appear, the allowable range of values and a short description.

This command set is presented here as it appears in the Instruction Manual dated 1996   Ver 0196-2

a. Command Set Formats

HH:MM.T   Example: 05:47.4
    Range: 00:00.0 to 23:59.9
        Hours, minutes, and tenths of minutes.

sDD*MM   Example: +45*59
    Range: -90*00 to +90*00
        Signed degrees and minutes (the (*) represents ASCII 223 which appears on the hand controller
        as a degree symbol).

DDD*MM   Example: 254*09
    Range: 000*00 to 359*59
        Unsigned degrees and minutes.

HH:MM:SS   Example: 13:15:36
    Range: 00:00:00 to 23:59:59
          Hours, minutes, and seconds.

MM/DD/YY   Example: 02/06/92
    Range: 01/01/00 to 12/31/99 (see description)
        Month, day, and year. The two digit year indicates the following: 92 through 99 = 1992 through 1999
        and 00 through 91 = 2000 through 2091

sHH   Example: -5    Range: -24 to +24
    Signed hour offset.

 NNNN   Example: 3456
    Range: 0000 to 9999
        Four digit object number.

sMM.M   Example: -02.4
    Range: -05.5 to 20.0
        Signed magnitude value.

NNN   Example: 134
    Range: 000 to 200
        Three digit object size (minutes).

DD*   Example: 56*
    Range: 00* to 90*
        Higher' parameter (degrees).

TT.T   Example: 59.2
    Range: 56.4 to 60.1
        Tracking 'frequency'. Info

(missing command set format line in manual)
Example: CNGC1 976 SU DNEB MAG 3.9 SZ 66.0'
    Range: n/a
        Object information.

Ok    Example: 1
    Range: 0 or 1
        Status value returned after setting values. If the value is legal 1 is returned, otherwise 0 is returned.
 

b. General Telescope Information

Command ACK (ASCII 6)
    Returns A, L, P or G
        Gets alignment status, A for alt-azm, L for land, P for polar, G for German mount polar.

Command   :GR#
    Returns +HH:MM.T#
        Gets the current Right Ascension.

A Mapug-Astronomy post indicated that for the 3.34L ROMS the format is  +HH:MM:SS# for RA
And the format for Declination is  sDD*MM'SS#.  Thus adding seconds and arc seconds.

Command   :GD#
    Returns sDD*MM#
        Gets the current declination.

Command   :GA#
    Returns sDD*MM#
        Gets the current altitude.

Command   :GZ#
    Returns DDD*MM#
        Gets the current azimuth.

Command   :GS#
    Returns HH:MM:SS#
        Gets the current sidereal time.

Command   :SS HH:MM:SS#
    Returns Ok
        Gets the sidereal time.

Command   :GL# :Ga#
    Returns HH:MM:SS#
        Gets the local time either in 24 hour (GL) or 12 hour (Ga) format.

Command   :SL HH:MM:SS#
    Returns Ok
        Sets the local time.   NOTE: The parameter should always be in 24 hour format.

Command   :GC#
    Returns MM/DD/YY#
        Gets the calendar date.

Command   :SC MM/DD/YY#
    Returns Ok (see description)
        Sets the calendar date.

        NOTE: After the Ok, if the date is valid, two strings will be sent. The first will contain the message
        "Updating planetary data," the second (sent after the planetary calculations) will contain only blanks.
        Both strings will be terminated by the (*) symbol.

Command   :Gt#
    Returns sDD*MM#
        Gets the latitude of the currently selected site.

Command   :St sDD*MM#
    Returns Ok
        Sets the latitude of the currently selected site.

Command   :Gg#
    Returns DDD*MM#
        Gets the longitude of the currently selected site.

Command   :Sg DDD*MM#
    Returns Ok
        Sets the longitude of the currently selected site.

Command   :GG#
    Returns sHH#
        Gets the offset from Greenwich Mean Time.

Command   :SG sHH#
    Returns Ok
        Sets the offset from Greenwich Mean Time.

Command   :W1# :W2# :W3# :W4#
    Returns Nothing
        Sets the current site number.
 

c. Telescope Motion

Command   :Mn#    :Ms#    :Me#    :Mw#
    Returns Nothing
        Starts motion in the specified direction at the current rate.

Command   :MS#
    Returns 0, 1, or 2 (see description)
        Slews telescope to current object coordinates. 0 is returned if the telescope can complete the slew,
        1 is returned if the object is below the horizon, and 2 is returned if the object is below the 'higher'
        limit. If 1 or 2 is returned, a string containing an appropriate message is also returned.

Command   :Qn#    :Qs#    :Qe#    :Qw#
    Returns Nothing
        Stops motion in the specified direction. Also stops the telescope if a slew to object is in progress.

Command   :Q#
    Returns Nothing
        Stops a slew to an object.

Command   :RG#    :RC#    :RM#    :RS#
    Returns Nothing
        Sets the motion rate to guide (RG), center (RC), find (RM), or slew (RS).
 

d. Library/Objects

Command   :Gr#
    Returns HH:MM.T#
        Gets object Right Assension

Command   :Sr HH:MM.T#
    Returns Ok
        Sets object Right Ascension.

A Mapug-Astronomy post indicated that for the 3.34L ROMS the format is  +HH:MM:SS# for RA
And the format for Declination is  sDD*MM'SS#.  Thus adding seconds and arc seconds.

Command   :Gd#
    Returns sDD*MM#
        Gets object Declination.

Command   :Sd sDD*MM#
    Returns Ok
        Sets object Declination.

Command   :CM#
    Returns (see description)
        Sync. Matches current telescope coordinates to the object coordinates and sends a string indicating which
        object's coordinates were used.

Command   :Gy#
    Returns GPDCO#
       Gets the 'type' string for the FIND operation. A capital letter means that the corresponding type is selected
       while a lower case letter indicates it is not.

Command   :Sy GPDCO#
    Returns Ok
        Gets the •type' string for the FIND operation.

Command  :Gq#
    Returns SU#,  EX#,  VG#,  GD#,  FR#,  PR#  or VP#
        Gets the current minimum quality for the FIND operation

Command   :Sq#
    Returns Nothing
        Steps to the next minimum quality for the FIND operation.

Command   :Gh#
    Returns DD*#
        Gets the current 'higher' limit.

Command  :Sh DD#
    Returns Ok
        Sets the current 'higher' limit.

Command   :Gb#    :Gf#
    Returns sMM.M#
        Gets the brighter (Gb) or fainter (Gf) magnitude limit for the FIND operation.

Command   :Sb sMM.M#    :Sf sMM.M#
    Returns Ok
        Sets the brighter (Gb) or fainter (Gf) magnitude limit for the FIND operation.

Command   :Gl#    :Gs#
    Returns NNN*
        Gets the larger (GI) or smaller (Gs) size limit for the FIND operation.

Command   :SI NNN#    :Ss NNN#
    Returns Ok
        Sets the larger (GI) or smaller (Gs) size limit for the FIND operation.

Command   :GF#
    Returns NNN#
        Gets the field radius of the FIELD operation.

Command   :SF NNN#
    Returns Ok
        Sets the field radius of the FIELD operation.

Command   :LF#
    Returns Nothing
        Starts a FIND operation.

Command   :LN#
    Returns Nothing
        Finds the next object in a FIND sequence.

Command   :LB#
    Returns Nothing
        Finds the previous object in a FIND sequence.

Command   :Lf#
    Returns (see description)
        Performs a FIELD operation returning a string containing the number of objects in the field and the
        object that is closest to the center of the field.

Command   :LC NNNN#    :LM NNNN#    :LS NNNN#
    Returns Nothing
        Sets the object to the CNGC (LC), Messier (LM), or Star (LS) specified by the number. Planets are
        •stars' 901-909.

Command   :Ll#
    Returns Object Information
        Gets the current object information.
 

e. Miscellaneous

Command   :B+#    :B-#    :B0#    :B1#    :B2#    :B3#
    Returns Nothing
        Increases (B+) or decreases (B-) reticle brightness, or sets to one of the flashing modes (B0, B1, B2 or B3).

Command   :F+#    :F-#    :FQ#    :FF#    :FS#
    Returns Nothing
        Starts focus out (F+), starts focus in (F-), stops focus change (FQ), sets focus fast (FF) or focus slow (FS)

Command   :GM#    :GN#    :GO#    :GP#
    Returns XYZ#
        Gets site name (XYZ). M through P correspond to 1 through 4.

Command   :SM XYZ#    :SN XYZ#    :SO XYZ#    :SP XYZ#
    Returns Ok
        Sets site name.

Command   :GT#
    Returns TT.T#
        Gets the current track 'frequency'.

Command   :ST TT.T#
    Returns Ok
        Sets the current track 'frequency'.

Command   :TM#    :TQ#    :T+#    :T-#
    Returns Nothing
        Switch to manual (TM) or quartz (TM). Increment (T+) or decrement (T-) manual frequency by one tenth.

Command   :Gc#
    Returns (12) or (24)
        Get 12/24 hour status of clock.

Command   :H#
    Returns Nothing
        Toggle 12/24 hour mode.

Command   :P#
    Returns "HIGH PRECISION" when ON  "LOW PRECISION" when OFF
        Toggles the High Precision Mode ON or OFF.

Command   :U#
    Returns Nothing
        Toggles the long format ON or OFF.
            When the long format is active, whenever a request to send or receive position data, the following format is used:

HH:MM:SS Example: 05:47:45
Range: 00:00.0 to 23:59:59
Hours, minutes, and seconds.
sDD*MM:SS Example: +45*59:45
Range: -90*00 to +90*00
Signed degrees, minutes, and seconds (the'*' represents ASCII 223 which appears on
the handbox as a degree symbol).
DDD*MM:SS Example: 254*09:45
Range: 000*00 to 359*59:59
Unsigned degrees, minutes, and seconds.
Command   :Lo N#
    Returns Ok
        Sets the NGC object library.  0 is the NGC library, 1 is the IC library and 2 is the UGC library.  This operation
        is successful only if the user has a version of the software that includes the desired library.

Command   :Ls N#
    Returns Ok
        Sets the STAR object library type. 0 is the STAR library; 1 is the SAO library, and 2 is the GCVS library. This
        operation is successful only if the user has a version of the software that includes the desired library.
 

f. Keypad Hand Controller Specific

Command   :D#
    Returns (see description)
        Gets the distance 'bars' string.

Command   :$Q (1-5)#
    Returns Nothing
        Toggles Smart Drive status.

Command   :?#
Command   :?+#
Command   :?-#
    Returns Page of Help Information
        Starts (??) or moves through (?+ or ?-) Help.

Command   : G0#
Command   : G1#
Command   : G2#
    Returns Alignment Menu Entry
        Used to implement alignment menu
 
 

LX200 Demo Program

The RS-232 interface communicates with your computer at 9600 Baud Rate, Parity = None, 8 Data Bits, 1 Stop Bit.
For those who are familiar with programming, the LX200 Command Set is written in ASKII character format and
can be used to write your own programs.  The LX200 Demo Program is written in Quick Basic and is intended to
demonstrate how commands can be sent to the telescope and information received from the telescope.  It is not a
"polished" program and does not incorporate all of the RS-232 features available.  The program is set-up to operate
on serial port 2 (COM2). To operate on serial port 1 (COM1) line 4 should be changad from "COM2 to "COM1.
The program is as follows:  Please note that Meade Instruments does not support these programs, or programs that
you may write in any way. For questions relating to after-market software programs, refer back to those manufacturers.
 

LX200 Test Program

Once you have the RS-232 cable constructed you will want to test the cable. Below is a simple program called "LX200
TEST" that is written in GW Basic programming language and will work with IBM compatible computers. LX200 TEST
is an effective program to fully check the RS-232 line communications from your personal computer to the LX200,
allowing you to concentrate on de-bugging your RS-232 cable.

To enter the following program, first load BASIC or GWBASIC (which ever your computer system uses), then type in the
following program. When complete, be sure to save the program as "LX200TST.BAS."

10     CLS
20     DEFINT A-X
30     OPEN "COM1:9600,N,8,1,CDO,CSO,DSO,RS," FOR RANDOM AS #1
50     key1$ = INKEY$: IF key1$ = * * THEN GOTO 50
60     REM Key 1 loop
70     IF key1$ = CHR$(119)  THEN GOSUB 200:   REM "w" key
80     IF key1$ = CHR$(101)  THEN GOSUB 200:   REM "e" key
90     IF key1$ = CHR$(110)  THEN GOSUB 200:   REM "n" key
100   IF key1$ = CHR$(115)  THEN GOSUB 200:   REM "s" key
105   IF key1$ = "x" THEN END: REM To exit test.
110   GOTO 50   REM  return to Key 1 loop
120   END
200   REM.Key 1 direction printouts to COM 1
210   REM west
220   IF key1$ = "w"  THEN  a$ = "#:Mw#"  : PRINT #1, a$:  REM GO west
230   REM east
240   IF key1$ = "e"   THEN  a$ = "#:Me#"   : PRINT #1, a$:  REM GO east
250   REM north
260   IF key1$ = "n"   THEN  a$ = "#:Mn#"   : PRINT #1, a$:  REM GO north
270   REM south:
280   IF key1$ = "s"   THEN  a$ = "#:Ms#"    : PRINT #1, a$:  REM GO south
290   key1$ = INKEY$:
300   IF key1$ = CHR$(32)  THEN  GOTO  400  ELSE  GOTO  200
400   REM This stops motion (by hitting SPACE bar).
410   B$ = "#:Qe#"  : PRINT #1, B$
420   B$ = "#:Qw#" : PRINT #1, B$
430   B$ = "#:Qn#"  : PRINT #1, B$
440   B$ = "#:Qs#"  : PRINT #1, B$
450   RETURN
460   END

To use the above program, connect the completed cable to your PC serial port and to the LX200 RS-232 Port. Load BASIC (or GWBASIC), if not already loaded, and run "LX200TST.BAS - " Nothing will appear on the computer screen. Press any one of the N, S, E, or W (lower case) keys on your PC keyboard, this will move the LX200 North, South, East, or West respectively. Press the space bar on the PC keyboard to stop. Press X to exit the program.  If the LX200 does not respond to the N, S, E, or W keys, be sure the CAPSLOCK is OFF. If it still does not work, check the PC serial port pinouts for your computer to be sure they are wired correctly to the LX200 6 line connector.   With a successful check-out of the PC link with the LX200 using "TEST", you are now ready to write your own software program using the LX200 Command Set or to use the sample program called "DEMO" that is written in Quick Basic software language.

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