cmcgrath5035

Homing: I sort of understand your objective but believe it is incompatible with how the homing command works. The most prevalent use for tinyG ia XYZ milling machines, with support for rotational axes as well but few well defined use cases.
Many users implement only X,Y homing, no Z switches. There is only one homed state, yes/no. So issuing a G28.2 homes specified axes, assumes axes not on the list are not home-able (no switches) and sets the homed state if the specified axes complete successfully.
It is not clear to me how to make it work for your use case.

LabView and I/O – When you say ” I query the serial port for how much in the buffer and read that out. “, are you referring to the Labview receive serial buffer or the tinyG transmit serial buffer?
There is no “some back-and-forth in the background I’m not aware of.” beyond Xon/Xoff or RTS/CTS hardware level flow control on the tinyG side.

confusing indeed

So in tinyG FW (and Hardware) space, there is a command, defa=1, that when executed copies the compiled set of defaults into EEPROM, making them current. Used on occasions when EEPROM gets corrupted. The compiled in defaults are almost never what real users want/need.
A few folks have gone to the trouble of compiling their own version of the tinyG FW with their stable machine setting compiled in, so that defa=1 reverts the machine to their native setup.
It is always good to keep a file around on you host computer of all the parameter settings that are working well for you. That would be a $$ parameter dump.

I agree with Gallen66 that external drivers are not required for tinyG to run NEMA 23s, but you will get maximum stepper performance, should you need it, with those external drivers.
Many folks do run with external drivers, particularly those with long running (hours at a time) Gcodes controlling high current steppers.
If you choose not to use your external drivers, be sure to provide adequate moving air (a fan) for tinyG

It is a builders choice.

I’ll add that if you do run high current/high torque motors, you should routinely check fastener torque, particularly pulley set screws.
It’s not 100% clear that some of the machine designs in service were designed to handle the power (torque) that is available these days.

• This reply was modified 7 years ago by cmcgrath5035.

A axis parameters are displayed, in cli mode, with $a command.

I don’t understand your comment

“The rotary stage should be in mode 2 and act simply like the linear stages.”

Axis modes are defined here: https://github.com/synthetos/TinyG/wiki/TinyG-Configuration-for-Firmware-Version-0.97#xam—axis-mode

Gcode movements for rotational axes are in degrees, G1 A3 is a 3 degree movement in standard mode. $aam=1. Use $3tr (in your case, if A axis stepper is connected to motor 3) to implement gearing ratio from stepper to output shaft.
The Gcode specifies movement of the output shaft.

If you prefer to create a custom Gcode stream that specifies linear movement, e.g. G1 A5 to move the A axis 5mm , then you can set $aam=3 (radius mode) and parameter $ara is set based on this definition https://github.com/synthetos/TinyG/wiki/TinyG-Configuration-for-Firmware-Version-0.97#ara—radius-value

I don’t know of any ‘standard’ tool chain that would generate that Gcode for you

To be honest, first person I have seen using rotary axis limits.
This Link https://github.com/synthetos/TinyG/wiki/TinyG-Configuration-for-Firmware-Version-0.97#xtn-xtm—travel-minimum-travel-maximum says setting min and max to same value means “no limits, which may explain behavior in your other post

You have both motor 3 and motor 4 mapped to A axis and enabled.
Is this really true?. I’m not sure it would make a difference if M4 were not connected to anything.

You have Motor 3 mapped to A axis and A axis in radius mode, Radius = 0.1989 deg, which is interpreted as move 1/.1989 degrees when G1 A1 is sent. Re-read how $3tr =2 is interpreted for a rotary axis.
https://github.com/synthetos/TinyG/wiki/TinyG-Configuration-for-Firmware-Version-0.97#1tr—travel-per-revolution
I am not 100% clear if your movement described is rotary stepper or rotary output after gear reduction

When I read

When I send the command G1 F100 A1 it moves more than 360 degrees instead of one degree.

I sort of think you should be in $aam=1, so that G1 A1 means 1 degree of movement requested.

• This reply was modified 7 years, 1 month ago by cmcgrath5035.

OOps, the link you posted points to this thread, not your Parameters dump

Not that it should really matter for this discussion, are we discussing a tinyG or G2core machine here? I ask because tinyG does not support $_mi=16, but you are not using $_mi=16 either.
Also, I will assume you are using the onboard tinyG drivers, or a Gshield/DUE hardware setup. If Gshield, the microstepping pins are all open, thus $_mi=8

Also assuming from what you show that $3ma=3, mapping motor 3 to A axis

Can you verify assumptions so far, or describe what is different?

Can you provide all the motor 3 and all the A axis parameters?
That would be results of $3 command and $a command
Or, Dump all parameters $$ , copy them to a Cloud drive and provide a URL for viewing.