cmcgrath5035

There are numerous bug fixes and enhancements accumulated into build 438.02.

I think I would run some test cuts with your serious Gcode with FW 438.02.

On the other hand, if your first tinyG is performing for you, then perhaps your projects don’t intersect with the fixed bugs.

I make a guess that C33 is a SMD chip capacitor.

A good reflow solder joint is very robust, so if the device got knocked off mechanically, it could be the device to pwb joint, or could be a de-lamination of the capacitor’s ceramic body from the metalized end cap. Probably not a good idea to attempt re-soldering the old component.
You may be able to tack on a small leaded component of the correct capacitance.

To more fully attempt, you need to determine what tinyG version you have.
For reference, look here:

https://github.com/synthetos/TinyG/tree/master/hardware

From the correct schematic you can determine what capacitance is required.

From there you can see the different versions of V7 and V8.

On the road at the moment, will give a harder look in 24 hrs.

I suggest you move to tinyG fw 438.02 (current edge)and give it a try.

Quick look around finds the AD eval board and this

http://www.ebay.com/itm/like/191303685123?lpid=82

Pecs are a tad confusing. USB2 compatible, but only up to 12Mbps.

Well ouch, that’s not a fun way to end your CNC session.

I have been a bit concerned myself as I research adding a DC spindle to my machine, which means a direct 3.3V logic connection to the spindle controller, which in turn has its own 48V power supply and “not always clear” polarity and ground references for the spindle drive side.

The USB Hub is a good idea, but I’m not sure I trust a run of the mill low cost hub to necessarily provide the desired isolation either.

Anyone else with experience here, and good solutions, please comment.

tinyG support – Not that I have seen and there is no I/O available so answer is likely No.

You should follow the directions from this Post:

https://www.synthetos.com/topics/tgfx-new-download-page/

There you will find the most recent build of tgFX that runs only under 64bit Windows.

You should also take a look at Chilipeppr.

https://github.com/synthetos/TinyG/wiki/Chilipeppr

tgFX has an unclear future and there are still bugs with the current build.

• This reply was modified 10 years, 2 months ago by cmcgrath5035.

Here are some items to think about, I have not implemented but would probably head down this path if trying myself. An underlying assumption is that you want to run ‘stock’ tinyG FW, rather than do massive tweaks to the internals.

First, the way I read your statement

…. i can not use spindle/coolant on off pin for z axis because they are used for other purpose.

is that both the Spindle ON/OFF pin and the Coolant ON/OFF pin are used by other functions under Gcode control.
Be aware that the pwm signal, intended to drive an external spindle driver, is logically connected to Spindle ON/OFF; e.g. Spindle ON – PWM active, Spindle OFF, PWM not active.

Since you are needing to drive, with precision, a Z axis, I don’t see how a crude implementation via spindle on/off would work for you even if the PWM signal were logically available.

I would suggest your best bet is to free up one of the Motor channels in tinyG, by driving your two X axis steppers from one channel, with one motor reversed by wiring it so. Two possible implementations:
1. If NEMA 17 motors, it should be possible to drive two motors wired to one tinyG driver. This technique was used early on by experimenters building dual X machines but having only 3 drivers available, such as GRBL/Gshield. You might have to turn up the current pot on that channel. Be mindful of device cooling if you run it hard.
2. A more robust method would be to pick off the Stepper driver signals ahead of the drivers (header on tinyG), perhaps buffer them (they are 3.3V logic) and use 2 external driver devices, one for each X motor. Several folks use external drivers for higher power steppers. A place to start might be to review Pololu individual drivers, there are many similar sub-assemblies available.

TinyG schematics are available on GIThub.

• This reply was modified 10 years, 2 months ago by cmcgrath5035.