Topics

New project GM8 with PM steppers


JoAnn
 

I have had a GM8 base for a couple years now. It is just the base/RA assembly and now I have a saddle. My intention is to use as a high end star tracker for a camera and small scope or lens. I have had trouble finding a way to get the right size coupler to the worm as the standard ones are too big in diameter. Also, I needed a gear reduction as the worm gear is only 180 teeth so the direct connect would not be good enough for imaging. The project has been shelved for a couple years. 
I just picked up a little solar scope so now I have renewed my motivation. 
I just got a line on a used original hurst PM stepper motor with 150 gear reduction. My plan is to use this with OnStep. I'll manually point at the target but be able to use ASCOM to platesolve and then make minor slews in RA to center target. The DEC will still be all manual but that is not an issue for my purpose. 
The motor is a unipolar motor but I have used the same motor with a arduino focuser by simply connecting the 4 wires and not connecting the center tap thus making it a bipolar motor. 
I'll keep folks updated here on progress. 
Looking forward to using OnStep again! 
This attached pic show the servo motor attached, that will be replaced. 


Gildo Bosi
 

For my GM8 I used a 1.8 ° / step stepper motor with GT2 belt reduction (16/60).
For coupling with the worm screw, the Oldham Huco size 13 joints can be used
(Huco 500.13 - select the input and output shaft diameters) or the original Losmandy Oldham couplings.

Using LV8729 stepper modules with 128 microsteps:
GM8 step per degree: 48000.0 = 200 * 128 * 60/16 * 180/360
Using TMC2209 stepper modules with 64 microsteps:
GM8 step per degree: 24000.0 = 200 * 64 * 60/16 * 180/360
Note: TMC modules are able to further interpolate the steps internally.


Howard Dutton
 

On Wed, Aug 26, 2020 at 08:22 AM, JoAnn wrote:
The motor is a unipolar motor but I have used the same motor with a arduino focuser by simply connecting the 4 wires and not connecting the center tap thus making it a bipolar motor.
Probably better to connect the center tap to one of the ends for each motor coil, but yes that should work and it'll be very slow goto as you know.  No need for fancy drivers I'd use A4988's.


JoAnn
 

I got the hurst pm motor today. I have to make a cable to connect from the RJ12 to the mini PCB which has .1 headers. In the meantime I tested my miniPCB with one of my nema 17's to make sure it was all running, it was. Went to reprogram the Teensy 3.2  (stand alone off board) with the updated steps per etc, and my Teensy fried somehow after connecting with the USB. 

So I just ordered the WEMOS32 and CNC shield. I have made two focus controllers with that shield and an UNO so figured I'd give a try. I ordered the lv8729 driver as well to try using a nema 17 direct drive/128 microstepping. 
We will see which one works better. Again, only want to use as a sun scope or camera tracker. Don't need a lot of torque as I won't be doing GOTO's with the solar scope and as a camera tracker, I would be manually pointing then using platesolving to do final GOTO and framing. 

JoAnn


JoAnn
 

Probably better to connect the center tap to one of the ends for each motor coil, but yes that should work and it'll be very slow goto as you know.  No need for fancy drivers I'd use A4988's.
Howard. I could not figure out where to connect the center tap. There will be 2 wires, one for each coil. Using the WEMOS32/shield combo, where should these connect? I think though the torque might be more than enough for just the little solar scope converting to bipolar. seems to work just fine for my focuser. 


JoAnn
 

Also, do I need the PPS + DS3231 (RTC) module for basic tracking/guiding. 
Thanks, JoAnn. 


George Cushing
 

Not the RTC, that just gives the system temporal orientation needed for goto to you'll be using your internal clock. Don't think PPS would make much of a difference with the Hurst.

I'm using the MiniPCB1 for this project to duplicate the performance of the $200 DK-3 dual hand drive. 



These Vixen MT-1 clones are available from the EU for 30E each. A stripped down MiniPCB is all that's needed. 



The DK-3 drives have a 120:1 gear head and are designed for Uni or bipolar hook up. You might not even need 12V to drive them. 

To replace the MiniPCB the WEMOS32/CNC3 needs a v. reg., although there id something on the CNC3 and a handbox/guider port. Costs about half of the Teensy solution. So let us know how it goes.



JoAnn
 

George: I'm using the MiniPCB1 for this project to duplicate the performance of the $200 DK-3 dual hand drive. 
that's funny, that's how I got into Onstep a few years back after I fried my CG5 dual axis controller. That was also my introduction to Arduino. Now I make things in 5 minutes. 

I got the WeMos R32 today along with the stepper drivers (LV8729 ) but the CNC shield is delayed and won't be here until Tuesday. The only problem I had programming it was not a problem at all. I did not realize that I could not use the bluetooth over iPhone. Kind of a bummer as I have the GOTOmote installed and I have only dated android devices. No matter though, I plan to just do platesolve and sync using a laptop and I can set time/date etc via ascom. 
Anyway, was all programmed in 5 minutes. What a treat this little board is! 


Howard Dutton
 
Edited

On Thu, Sep 3, 2020 at 05:17 PM, JoAnn wrote:
Probably better to connect the center tap to one of the ends for each motor coil, but yes that should work and it'll be very slow goto as you know.  No need for fancy drivers I'd use A4988's.
Howard. I could not figure out where to connect the center tap. There will be 2 wires, one for each coil. Using the WEMOS32/shield combo, where should these connect? I think though the torque might be more than enough for just the little solar scope converting to bipolar. seems to work just fine for my focuser. 
For bipolar half-coil within the link below you would use black/yellow for one coil and red/white for the other, green and blue are not connected.  You could also wire the other combination, center to end for the same.  As you can read below this results in the same torque and performance the motor would have with a unipolar driver.  As bipolar full coil the motor makes 1.4x more holding torque but doesn't hold onto that torque as well at higher RPM's.

https://www.orientalmotor.com/stepper-motors/technology/unipolar-bipolar-connections.html


JoAnn
 

For bipolar half-coil within the link below you would use black/yellow for one coil and red/white for the other, green and blue are not connected.  You could also wire the other combination, center to end for the same.  As you can read below this results in the same torque and performance the motor would have with a unipolar driver.  As bipolar full coil the motor makes 1.4x more holding torque but doesn't hold onto that torque as well at higher RPM's.

https://www.orientalmotor.com/stepper-motors/technology/unipolar-bipolar-connections.html
Thanks Howard. Seems like for this purpose, since I won't be slewing all over the place, using bipolar configuration for low speed torque id the best. Plus that wotks perfect on my moonstep focus motor which is identical (but smaller) motor and gearbox. 

JoAnn. 


JoAnn
 

worked on the mechanics this weekend as I don't have all the parts for the OnStep yet. Works great for visual and expect perfect for high speed video and live stacking astrophotography.


Mike Ahner
 

That's a very interesting setup, JoAnn!
Would you mind showing a little more detail into your "drain pipe" pier? :) 
How do you find the stability? 

It reminds me of Khalid's water resistant (with packing tape), cardboard OnStep cases. Very minimalist and use what you have philosophy in a hobby well known high cost solutions to simple problems.


Khalid Baheyeldin
 

On Sun, Sep 6, 2020 at 06:04 PM, Mike Ahner wrote:
Would you mind showing a little more detail into your "drain pipe" pier? :) 
How do you find the stability? 
Equally interesting is the pillow block DEC axis add on!


JoAnn
 

That's a very interesting setup, JoAnn!
Would you mind showing a little more detail into your "drain pipe" pier? :) 
How do you find the stability? 
I noticed that the underside of the GM8 had a recess that seemed to be the same dimensions as schedule 40 4" pipe. 20+ years ago I built a little pier out of this pipe. I dug it out of the "backyard dump" and simply placed the mount on the pipe and it was a near perfect fit. Stability is good enough for this purpose. I just plopped in on and tightened the 3 screws. THAT is not very secure so I move the tripod where I want it and them attach the mount. It is stored in my observatory so know one is going to knock it over or bump into it. The plywood round is attached to the tripod and the flange is attached to the plywood. 

mount pics

It reminds me of Khalid's water resistant (with packing tape), cardboard OnStep cases. Very minimalist and use what you have philosophy in a hobby well known high cost solutions to simple problems.
I also had OnStep running in a cardboard box. I think Khalid's stole my idea :) There is a ready made acrylic case made for the WEMOS and CNC shield  for $9 that I have used for my focuser projects.

focuser footprint using uno/cnc

 


JoAnn
 

On Sun, Sep 6, 2020 at 03:28 PM, Khalid Baheyeldin wrote:
Equally interesting is the pillow block DEC axis add on!
I have a 4.65 byers gear that I am still trying to design into the pillow block assembly. 


Khalid Baheyeldin
 

On Mon, Sep 7, 2020 at 01:15 PM, JoAnn wrote:
It reminds me of Khalid's water resistant (with packing tape), cardboard OnStep cases. Very minimalist and use what you have philosophy in a hobby well known high cost solutions to simple problems.
I also had OnStep running in a cardboard box. I think Khalid's stole my idea :)
I did.

Initially I wanted a food storage container case, but could not find one that would it, then found the perfect sized
cardboard box in the basement, so used that with clear packing tape to protect from dew.

Then Dave created his 3D printed case, and I moved to that, after a year or 18 months of cardboard ...


Khalid Baheyeldin
 

JoAnn,

Your unique GM8 project is now in the showcase.


JoAnn
 

On Mon, Sep 7, 2020 at 10:32 AM, Khalid Baheyeldin wrote:
JoAnn,

Your unique GM8 project is now in the showcase.
Well, it is not done yet! OnStep not completed :) 


Khalid Baheyeldin
 

On Mon, Sep 7, 2020 at 03:00 PM, JoAnn wrote:
Well, it is not done yet! OnStep not completed :)
Yeah, but the mechanical design is done, and you will power one axis only.
That may prove useful for those not needing full GOTO functionality already.


JoAnn
 

So, I got the shield today (x2). Just bench testing it, I am not able to get the motors to respond. I have good 12V into the shield, and driver (l8729) pots are measuring current I have adjusted on the fly, changed them out ( I have 5). Both android OnStep and Sky Safari Plus are communicating. I can slew around in Sky Safari, sync and GOTO so that tells me the WEMOS board is working. I have RA axis as Y and DEC as X. No matter though because I tried switching them. I tried my NEMA17 and my hurst PM motor. I have the jumpers set for micro stepping. I also have tracking to ON upon start just for testing to be easier. I did cut the R1 resistor off. 
There is a link to some photos including the calculation spreadsheet (I've tried many many variations. )

look at the last 4 photos

Is there something I am missing? 

// firmware info, these are returned by the ":GV?#" commands
#define FirmwareDate          __DATE__
#define FirmwareVersionMajor  4
#define FirmwareVersionMinor  15      // minor version 0 to 99
#define FirmwareVersionPatch  "h"     // for example major.minor patch: 1.3c
#define FirmwareVersionConfig 3       // internal, for tracking configuration file changes
#define FirmwareName          "On-Step"
#define FirmwareTime          __TIME__

// ---------------------------------------------------------------------------------------------------------------------------------
// Configuration for OnStep
 
/*
 *          For more information on setting OnStep up see http://www.stellarjourney.com/index.php?r=site/equipment_onstep 
 *                      and join the OnStep Groups.io at https://groups.io/g/onstep
 * 
 *           *** Read the compiler warnings and errors, they are there to help guard against invalid configurations ***
*/
 
// ---------------------------------------------------------------------------------------------------------------------------------
// ADJUST THE FOLLOWING TO CONFIGURE YOUR CONTROLLER FEATURES ----------------------------------------------------------------------
// <-Req'd = always must set, <-Often = usually must set, Option = optional, Adjust = adjust as req'd, Infreq = infrequently changed
 
// PINMAP ---------------------------------------------------------- see https://onstep.groups.io/g/main/wiki/6-Configuration#PINMAP
//   *** See the matching Pins.xxx.h file for your setup (found by looking in src/pinmaps/Models.h) with detailed information ***
//   *** to be sure it matches your wiring.            *** USE AT YOUR OWN RISK ***                                           ***
 
//      Parameter Name              Value   Default  Notes                                                                      Hint
#define PINMAP                        MaxESP2 //    OFF, Choose from: MiniPCB, MiniPCB2, MaxPCB, MaxPCB2, STM32Blue,             <-Req'd
                                          //         Ramps14, MaxESP2, MaxESP3.  Check Constants.h for more info.
 
// SERIAL PORT COMMAND CHANNELS ------------------------------------ see https://onstep.groups.io/g/main/wiki/6-Configuration#SERIAL
#define SERIAL_A_BAUD_DEFAULT        9600 //   9600, n. Where n=9600,19200,57600,115200 (common baud rates.)                  Infreq
#define SERIAL_B_BAUD_DEFAULT        9600 //   9600, n. See (src/HAL/) for your MCU Serial port # etc.                        Option
#define SERIAL_B_ESP_FLASHING         OFF //    OFF, ON Upload ESP8266 WiFi firmware through SERIAL_B with :ESPFLASH# cmd.    Option
#define SERIAL_C_BAUD_DEFAULT         ON //    OFF, n, ON for ESP32 Bluetooth.                                               Option
#define SERIAL_C_BLUETOOTH_NAME  "OnStep" // "On..", Bluetooth device name for ESP32.                                         Option
 
// MOUNT TYPE -------------------------------------------------- see https://onstep.groups.io/g/main/wiki/6-Configuration#MOUNT_TYPE
#define MOUNT_TYPE                    GEM //    GEM, GEM for German Equatorial, FORK for Equatorial Fork, or ALTAZM          <-Req'd
                                          //         Dobsonian etc. mounts. GEM Eq mounts perform meridian flips.
 
// USER FEEDBACK -------------------------------------------- see https://onstep.groups.io/g/main/wiki/6-Configuration#USER_FEEDBACK
#define LED_STATUS                     ON //     ON, Blinks w/sidereal tracking otherwise steady on indicates activity.       Option
#define LED_STATUS2                   OFF //    OFF, ON Blinks 1s interval w/PPS sync, steady for gotos, off if in standby.   Option
#define LED_RETICLE                   OFF //    OFF, n. Where n=0..255 (0..100%) activates feature sets default brightness.   Option
#define BUZZER                        OFF //    OFF, ON, n. Where n=100..6000 (Hz freq.) for piezo speaker. ON for buzzer.    Option
#define BUZZER_STATE_DEFAULT          OFF //    OFF, ON Start with piezo buzzer/speaker enabled.                              Option
 
// TIME AND LOCATION -------------------------------------------------- see https://onstep.groups.io/g/main/wiki/6-Configuration#TLS
#define TIME_LOCATION_SOURCE          OFF //    OFF, DS3231 (I2c,) DS3234 (Spi,) TEENSY (T3.2 internal,) or GPS source.       Option
                                          //         Provides Date/Time, and if available, PPS & Lat/Long also.
 
// SENSORS -------------------------------------------------------- see https://onstep.groups.io/g/main/wiki/6-Configuration#SENSORS
// * = also supports ON_PULLUP or ON_PULLDOWN to activate MCU internal resistors if present.
#define WEATHER                       OFF //    OFF, BME280 (I2C 0x77,) BME280_0x76, BME280_SPI (see pinmap for CS.)          Option
                                          //         BMP280 (I2C 0x77,) BMP280_0x76, BMP280_SPI (see pinmap for CS.)
                                          //         BME280 or BMP280 for temperature, pressure.  BME280 for humidity also.
                                          
#define TELESCOPE_TEMPERATURE         OFF //    OFF, DS1820, n. Where n is the DS1820 s/n for focuser temperature.            Adjust
 
#define HOME_SENSE                    OFF //    OFF, ON*. Automatically detect and use home switches. For GEM mode only.      Option
#define HOME_SENSE_STATE_AXIS1       HIGH //   HIGH, State when clockwise of home position, as seen from front. Rev. w/LOW.   Adjust
#define HOME_SENSE_STATE_AXIS2       HIGH //   HIGH, State when clockwise of home position, as seen from above. Rev. w/LOW.   Adjust
                                          //         Signal state reverses when travel moves ccw past the home position.
 
#define LIMIT_SENSE                   OFF //    OFF, ON* limit sense switch close to Gnd stops gotos and/or tracking.         Option
#define LIMIT_SENSE_STATE             LOW //    LOW, For NO (normally open) switches, HIGH for NC (normally closed.)          Adjust
 
#define PEC_SENSE                     OFF //    OFF, ON*, n, sense digital OR n=0 to 1023 (0 to 3.3V or 5V) analog threshold. Option
#define PEC_SENSE_STATE              HIGH //   HIGH, Senses the PEC signal rising edge or use LOW for falling edge.           Adjust
                                          //         Ignored in ALTAZM mode.
 
#define PPS_SENSE                     OFF //    OFF, ON* enables PPS (pulse per second,) senses signal rising edge.           Option
                                          //         Better tracking accuracy especially for Mega2560's w/ceramic resonator.
 
// ST4 INTERFACE ------------------------------------------------------ see https://onstep.groups.io/g/main/wiki/6-Configuration#ST4
// *** It is up to you to verify the interface meets the electrical specifications of any connected device, use at your own risk ***
#define ST4_INTERFACE                 OFF //    OFF, ON, ON_PULLUP enables interface. <= 1X guides unless hand control mode.  Option
                                          //         During goto btn press: aborts slew or continue meridian flip pause home
#define ST4_HAND_CONTROL              OFF //    OFF, ON for hand controller special features and SHC support.                 Option
                                          //         Hold [E]+[W] btns >2s: Guide rate   [E]-  [W]+  [N] trk on/off [S] sync
                                          //         Hold [N]+[S] btns >2s: Usr cat item [E]-  [W]+  [N] goto [S] snd on/off
#define ST4_HAND_CONTROL_FOCUSER      OFF //    OFF, ON alternate to above: Focuser move [E]f1 [W]f2 [N]-     [S]+            Option
 
// GUIDING BEHAVIOUR ---------------------------------------------- see https://onstep.groups.io/g/main/wiki/6-Configuration#GUIDING
#define GUIDE_TIME_LIMIT                0 //      0, No guide time limit. Or n. Where n=1..120 second time limit guard.       Adjust
#define GUIDE_DISABLE_BACKLASH        OFF //    OFF, Disable backlash takeup during guiding at <= 1X                          Option
 
// TRACKING BEHAVIOUR -------------------------------------------- see https://onstep.groups.io/g/main/wiki/6-Configuration#TRACKING
#define TRACK_AUTOSTART               ON //    OFF, ON Start with tracking enabled.                                          Option
#define TRACK_REFRACTION_RATE_DEFAULT OFF //    OFF, ON Start w/atmospheric refract. compensation (RA axis/Eq mounts only.)   Option
#define TRACK_BACKLASH_RATE            25 //     25, n. Where n=2..50 (x sidereal rate) during backlash takeup.               Option
                                          //         Too fast motors stall/gears slam or too slow and sluggish in backlash.
 
// SYNCING BEHAVIOUR ---------------------------------------------- see https://onstep.groups.io/g/main/wiki/6-Configuration#SYNCING
#define SYNC_CURRENT_PIER_SIDE_ONLY    ON //     ON, Disables ability of sync to change pier side, for GEM mounts.            Option
 
// SLEWING BEHAVIOUR ---------------------------------------------- see https://onstep.groups.io/g/main/wiki/6-Configuration#SLEWING
#define SLEW_RATE_BASE_DESIRED        2.0 //    1.0, n. Desired slew rate in deg/sec. Adjustable at run-time from            <-Req'd
                                          //         1/2 to 2x this rate, and as MCU performace considerations require.
#define SLEW_RATE_MEMORY              ON //    OFF, ON Remembers rates set across power cycles.                              Option
#define SLEW_ACCELERATION_DIST        5.0 //    5.0, n, (degrees.) Approx. distance for acceleration (and deceleration.)      Adjust
#define SLEW_RAPID_STOP_DIST          2.5 //    2.0, n, (degrees.) Approx. distance required to stop when a slew              Adjust
                                          //         is aborted or a limit is exceeded.
 
#define MFLIP_SKIP_HOME               OFF //    OFF, ON Goto directly to the destination without visiting home position.      Option
#define MFLIP_PAUSE_HOME_MEMORY       OFF //    OFF, ON Remember meridian flip pause at home setting across power cycles.     Option
#define MFLIP_AUTOMATIC_MEMORY        ON //    OFF, ON Remember automatic meridian flip setting across power cycles.         Option
 
// PARKING BEHAVIOUR ---------------------------------------------- see https://onstep.groups.io/g/main/wiki/6-Configuration#PARKING
#define STRICT_PARKING                OFF //    OFF, ON Un-parking is only allowed if successfully parked.                    Option
 
// MOTION CONTROL -------------------------------------------------- see https://onstep.groups.io/g/main/wiki/6-Configuration#MOTION
#define STEP_WAVE_FORM             SQUARE // SQUARE, PULSE Step signal wave form faster rates. SQUARE best signal integrity.  Adjust
 
// Stepper driver models (also see ~/OnStep/src/sd_drivers/Models.h for additional infrequently used models and more info.): 
// A4988, DRV8825, LV8729, S109, SSS TMC2209*, TMC2130* **, and TMC5160* ***
// * = add _QUIET (stealthChop tracking) or _VQUIET (stealthChop tracking & slew,) for example "TMC2130_VQUIET"
// ** = SSS TMC2130 if you choose to set stepper driver current (in mA) set Vref pot. 2.5V instead of by motor current as usual.
// *** = SSS TMC5160 you must set stepper driver current (in mA) w/ #define AXISn_TMC_IRUN (IHOLD, etc.)
 
// AXIS1 RA/AZM
// see https://onstep.groups.io/g/main/wiki/6-Configuration#AXIS1
#define AXIS1_STEPS_PER_DEGREE    14400.0 //  12800, n. Number of steps per degree:                                          <-Req'd
                                          //         n = (stepper_steps * micro_steps * overall_gear_reduction)/360.0
#define AXIS1_STEPS_PER_WORMROT     28800.0 //  12800, n. Number of steps per worm rotation (PEC Eq mode only:)                <-Req'd
                                          //         n = (AXIS1_STEPS_PER_DEGREE*360)/reduction_final_stage
 
#define AXIS1_DRIVER_MODEL            OFF //    OFF, (See above.) Stepper driver model.                                      <-Often
#define AXIS1_DRIVER_MICROSTEPS       OFF //    OFF, n. Microstep mode when tracking.                                        <-Often
#define AXIS1_DRIVER_MICROSTEPS_GOTO  OFF //    OFF, n. Microstep mode used during gotos.                                     Option
#define AXIS1_DRIVER_IHOLD            OFF //    OFF, n, (mA.) Current during standstill. OFF uses IRUN/2.0                    Option
#define AXIS1_DRIVER_IRUN             OFF //    OFF, n, (mA.) Current during tracking, appropriate for stepper/driver/etc.    Option
#define AXIS1_DRIVER_IGOTO            OFF //    OFF, n, (mA.) Current during slews. OFF uses same as IRUN.                    Option
#define AXIS1_DRIVER_REVERSE          OFF //    OFF, ON Reverses movement direction, or reverse wiring instead to correct.   <-Often
#define AXIS1_DRIVER_STATUS           OFF //    OFF, TMC_SPI, HIGH, or LOW.  Polling for driver status info/fault detection.  Option
 
#define AXIS1_LIMIT_MIN              -180 //   -180, n. Where n= -90..-270 (degrees.) Minimum "Hour Angle" for Eq modes.      Adjust
                                          //         n. Where n=-180..-360 (degrees.) Minimum Azimuth for AltAzm mode.
#define AXIS1_LIMIT_MAX               180 //    180, n. Where n=  90.. 270 (degrees.) Maximum "Hour Angle" for Eq modes.      Adjust
                                          //         n. Where n= 180.. 360 (degrees.) Maximum Azimuth for AltAzm mode.
 
// AXIS2 DEC/ALT
// see https://onstep.groups.io/g/main/wiki/6-Configuration#AXIS2
#define AXIS2_STEPS_PER_DEGREE    12800.0 //  12800, n. Number of steps per degree:                                          <-Req'd
                                          //         n = (stepper_steps * micro_steps * overall_gear_reduction)/360.0
 
#define AXIS2_DRIVER_MODEL            OFF //    OFF, (See above.) Stepper driver model.                                      <-Often
#define AXIS2_DRIVER_MICROSTEPS       OFF //    OFF, n. Microstep mode when tracking.                                        <-Often
#define AXIS2_DRIVER_MICROSTEPS_GOTO  OFF //    OFF, n. Microstep mode used during gotos.                                     Option
#define AXIS2_DRIVER_IHOLD            OFF //    OFF, n, (mA.) Current during standstill. OFF uses IRUN/2.0                    Option
#define AXIS2_DRIVER_IRUN             OFF //    OFF, n, (mA.) Current during tracking, appropriate for stepper/driver/etc.    Option
#define AXIS2_DRIVER_IGOTO            OFF //    OFF, n, (mA.) Current during slews. OFF uses same as IRUN.                    Option
#define AXIS2_DRIVER_POWER_DOWN       OFF //    OFF, ON Powers off 10sec after movement stops or 10min after last<=1x guide.  Option
#define AXIS2_DRIVER_REVERSE          OFF //    OFF, ON Reverses movement direction, or reverse wiring instead to correct.   <-Often
#define AXIS2_DRIVER_STATUS           OFF //    OFF, TMC_SPI, HIGH, or LOW.  Polling for driver status info/fault detection.  Option
#define AXIS2_TANGENT_ARM             OFF //    OFF, ON +limit range below. Set cntr w/[Reset Home] Return cntr w/[Find Home] Infreq
 
#define AXIS2_LIMIT_MIN               -90 //    -90, n. Where n=-90..0 (degrees.) Minimum allowed declination.                Infreq
#define AXIS2_LIMIT_MAX                90 //     90, n. Where n=0..90 (degrees.) Maximum allowed declination.                 Infreq

Thanks JoAnn