cmcgrath5035

Hmmm, please define “lost control”

From your top post, issuing $sys creates a proper looking response, so I conclude basic command interface is sort of working.

Are you sure CoolTerm and tinyG are running at same baud rate(115200)?

Changing $ej can be tricky, because tinyG auto switches between Text and JSON based on the format of a command from Coolterm to tinyG.
So send a text command, get text response; send JSON formatted command, get JSON formatted response

Zootalaws has described what it takes to make a heavy machine perform, perhaps you have something more modest.

Does your current setup print accurately, just too slowly?

$xvm, $yvm are maximum velocities. Does your Gcode explicitly issue slower speeds?
e.g. G0 x__ y__ F1000
Once sent to the machine, that F speed will remain in effect until changed by a subsequent command, e.g. G0 x__ y__ F3000

What CAM software do you use? Chilipeppr has a speed override capability, other interfaces may as well. Or go back to the source.

Q1 – Yes, the DUE should be able to interface to the 2 – 5v logic directly. Beware that G2Core is Enable active low (a.k.a. enable-bar). Not sure that is directly applicable with TB6600

Q2 – the micostep outputs are binary programming for the the driver device, does the TB6600 support that input?
Limit switch inputs are for a NO or NC switch . You need to provide some lead filtering similar to what is provided on tinyG or Gshield (R-C lpf)

Q3 – That lead is GrblEnable, name of the Gshield pin when Gshield is used on a UNO with Grbl.

Q4 – G2Core provides a o-100% Motor power control, similar to the pot ON tingG. See PL parameter at https://github.com/synthetos/g2/wiki/Configuring-0.99-Motors#summary
TB6600 may not support that

I used CoolTerm many moons ago. I do recall that on occasion I have to start CoolTerm, then reset tinyG to see the command prompt tinyG>.

My guess would be that the settings in your CoolTerm are not identical between your new desktop and your friends old laptop.
I am think settings like what to do when enter is hit. Append nothing, CR, CFLF, etc. Cool Term has a number of options like this

It might help if you capture a parameter dump with your once chance.
That would be $$ then a CR

I understand your baffle.
In a typical machine, none of the active devices (steppers, limit switches, spindles, etc) should have any electrical connection to the machine framework.

If you wanted to pursue understanding what was going on, I would start by attempting to understand in detail how your power supplies are connected.
The Low cost (relatively speaking) compact transformer-less DC supplies typically used in this space have a indeterminate relationship, output wise, to AC Line-in and Neutral. Some have their positive output sitting one one two diodes above at below Line in, while – output 24V below Neutral. Way back at your breaker box, Neutral and earth (green wire) are connected.
But other designs are just the opposite, – out is referenced to Neutral and + output 24V above neutral.
Very strange things can happen if you connect the wrong things together.

Review Limits

Placing a disconnect switch in series with stepper winding leads would not be a good long term idea. It would de-energize the motor, but tinyG would have no idea it was disconnected and would continue to run whatever Gcode job was running at the time.

Installing the limit switches per the Wiki would logically de-energize the motors.

Stopping or pausing a running Gcode job is non trivial and is typically handled by the CAM layer (machine controller) software. Chilipeppr and CNC.js are typical CAM environments for tinyG, but there are others.
Review this link Gcode

• This reply was modified 4 years, 11 months ago by cmcgrath5035.

I thought a bit more on your problem and wondered as well, you did say that motion terminated but did not say it was a flashing leds/ limit exceeded sort of event.

My guess would be that the coupled noise somehow affected code execution in the tinyG controller, although explaining how the program execution could remain ‘sane’ is a bit of a stretch. Best guess would be corruption of the dynamic part of the process (RAM values)while the tinyG FW and parameters, in non-volatile storage remained in-tact.