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I think what I might try with that, would be to figure out which traces on the motherboard are step and direction for each axis. I would cut each trace on the motherboard somewhere between the I.C. and the blue card edge connectors in locations where I'd have a chance of bridging the cut with solder in case I later wanted to undo it. This would tend to be near the solder points where the blue card edge connectors are soldered in. This is to prevent the original I.C. from interfering with the signals from LinuxCNC.

Then I would solder maybe 24 AWG wires to the solder pins of each step and direction on the back side of the card edge connectors for wiring into a 4 or 5 axis parallel port bob that can be bought at low cost.

This would allow the power and motor connections to stay original. Spindle and e-stop signals I would wire direct to the bob. Make sure to connect bob's ground to a common ground on that motherboard.

Hope that helps.

 

Nope, those are motor traces from drives to the connector, so that idea is a dud.
Cutting the step/dir traces on the drives or the main board then ?

Thank you for the interesting idea. I think it would not work to drive the stepper motor drivers from the blue Centronics connector because the drivers have each two Optocouplers, for STEP and DIR (see white frame on the front side of the driver board).

Below are some more pictures attached.

Good news for the RPi guys, should be back into the swing of things round mid to late February, once I've found which box has what.

It's a PITA looking for a place to stay in Oz. Gumbernment is bringing "skilled workers" to build new houses because of a housing shortage, but hasn't thought about where these people are going to live whilst they are building the "new houses". If someone can explain the thought process behind this policy I'd be quite interested.

I was starting to think I'd have to sell a lot of stuff.

Guess I might have been in a bit of a panic.

Thanks for the update — much appreciated.

That timeline works well for my planning. I’ll wait for the 7I84U and 7i96S restocks and proceed with the all-Mesa setup as discussed.

Thanks again for the clarification.

Probably most mature
forum.linuxcnc.org/show-your-stuff/48630...-io-expansion#267799

Direct link to Alex's github
github.com/AlexmagToast/LinuxCNC_ArduinoConnector

I made one based on a Arduino micro using a HID USB stack on the arduino, showed a few pictures on the forum, not much response so really couldn't be bothered documenting it.
To tell the truth I'm can't be sure whether I still have the source code.

Tormach uses a USB I\O module with their machines with Path Pilot, no experience with it so unable to give a details.

Arduino > USB Serial > Linuxcnc is a pretty well trodden path for non RT I\O.

A lot of VFD control is implemented via a USB to RS485 controller.

The only real issue with USB is it's implementation (protocol) from the beginning isn't, IMHO, a good candidate for RT applications. A lot of people who use a Mesa FPGA card take advantage of the Smart Serial cards available from Mesa. When used with a Ethernet interface it does give some isolation from the PC. And I've never had a card drop out.

I was under the impression you may have been writing a ground up driver that talks to the Linuxcnc stack in a more fault tolerant way, not just a simple serial type project.

Note our Email is borked for a while

7i84U is probably next week and the 7I96S about 3 weeks out

The blue short Centronics connector on the back of the case/on the board upper left, seems like it is for MPG and knowing how lazy chinese are, i would venture a guess at having step/sir pins for all drives on it, so grab the TB6600 datasheet and a DVM and measure continuance between those pins on the chip and on the connector.
That should save you a lot of time even if you do not have the connector for it as it is easy to solder wires to those connector pins.

Looks great. Took awhile to get that look?
Ya keep us updated.

Hi

I'm new to CNC machines. I want to mill 3D aluminum on a smallish budget. That is the reason why I bough this used machine, my first one. Since I don't want to learn and buy end-of-life software and I like the power and flexibility that comes with open source projects like LinuxCNC the decision to convert it was easy.

It is a Chinese 6040ZH router, 60x40cm bed, 4 axis, rod rails on all axis, 1.5kw spindle, 57BYGH56-4011YD stepper motors (1.26Nm holding torque, 2.8A), 24V system, running mach3 with a USB connection.
Here is a link:  www.lygroupchina.com/gantry-cnc-router/h...c-machine-1500w.html

 

I' ve decided not to invest much into the machine because it has some mechanical design flaws and try to make the best out of it.

1. It has rod rails and not linear guides
2. The leaver arm on Y-axis to the rod rails is bigger than it needs to be. The rods could have been placed higher  

 

Since the controller board runs with a USB-Connection there is no way to run it directly with LinuxCNC. I wanted to know if its possible to reuse the electrical components and it seems so, the stepper motor controllers and the VFD for the spindle. Untested so far.
My plan is to use a MESA i796S board. If you have another suggestion let me know. Unfortunately they are out of stock currently.
  
The stepper motor controllers are 20 pin modules that stick on some kind of motherboard which also hosts the Mach3 controller, namely a Mach3-R-V1.3. With some reverse engineering I'm confident that I could figure out the function of the pins of the stepper motor controllers. The IC of the drivers seems to be a TB6600HQ or a clone. It has a voltage range of 8-42V, supports operating current of 4.5A, about 150w. It says www.shyidiao.com on them.
 

Front side from left to right (with the heat spreader remove from the IC. On the bottom left are two optocouplers):
GND, +5V, Pulse, Direction, Stepper RED, Stepper BLUE, Stepper GREEN, Stepper BLACK, +24V, +24V

 
Back side from left to right (reversed direction from above):
+24V, +24V, Stepper BLACK, Stepper GREEN, Stepper BLUE, Stepper RED, GND, GND, GND, GND

The soldering joints are very likely determining the microstepping of the drivers. If the configuration is from left to right: 1, 1/2, 1/4, 1/8, 1/16 and 1/32 then they are set to a reasonable 1/8.

 
The spindle driver runs independent of the 24V system. It has two ways to receive an input:

1. an analog input with voltage range 0-5V, currently wired to a potentiometer to manually control the spindle
2. three digital inputs, allowing for 8 fixed speeds

The VFD has the marking Inverter_B_v07. Its pins seem to be from top to bottom:
+12V, +5V, i5V (analog Input), SGND (signal ground), FWD (run forward), REV (reverse), BCD2, BCD1, BCD0, ErrB, ErrA

LinuxCNC can handle the TB6600HQ so if its correct they should run with it. Also the spindle can either be run with the analog input or the 3 bit digital one. I still have to decide which one to use. I like the possibility to run the stepper drivers and motors with 36V. That could be a nice upgrade from 24V.
I need a controller board that can handle 4 axis, this VFD, at least one limit switch, touch probe, automatic tool setting and in the future the possibility to attach sensors to close the loop (linear glass scale). The MESA i796S should be able to do that.

A question that is still open to me is how to physically connect the drivers to the MESA board?

1. Buy these 20 Pin sockets and make a board with them? Probably costly and time consuming
2. Solder the connections directly to the pins on the module and attach them somehow. Dirty, easy, quick, downside is, I can't plug them back in the motherboard
3. Solder the connecting wires to the motherboard and plug the drivers into the board. Could be neat because the machine could be back ported to Mach3. Possible unwanted side effects on the board. Of course I would unplug the Mach3 controller chip.

Feel free to correct me or give suggestions etc. I hope the MESA cards are back in stock soon.

Bes

Thanks — that’s a good point. I did see that the 7i96 (non-S) is currently in stock and that it would work for THCAD-2 and encoder input.

That said, for this machine I’m trying to stay fully within the Mesa ecosystem with maximum flexibility and isolation, and to keep things future-proof in a noisy industrial environment. Even if I don’t strictly need 0–10V today, the added analog output and larger FPGA on the 7i96S make it more attractive for my long-term use.

If 7i96S restock is expected in the near term, I’m inclined to wait and standardize on that rather than mixing generations.

If you do not need the 0-10V analog output for VFD, there are in stock Mesa 7i96 without the S, they do have an encoder input:
store.mesanet.com/index.php?route=produc...oduct&product_id=311

No need for a bit file, only if you need non standard firmware.
That is from old Mesa boards that needed the firmware at startup, all new ones have that on board, many of them twice, just in case a bad flash messes up switch to the backup and flash again, correctly if possible.

Thanks Peter — one additional note: I also see that 7i96S and 7I84U are currently showing as out of stock on the Mesa store.

My preference is to stay fully within the Mesa ecosystem (rather than using generic BOBs), so if there are any expected restock timelines for 7i96S and 7I84U, or recommended current-production alternatives that keep a similar architecture, that would be very helpful for planning.

I can wait a bit if needed, but I’d like to avoid purchasing from Europe if these boards are expected to be restocked or revised in the near term.

Thanks Peter — that’s very helpful.

That aligns well with my use case. Since the IL-1000 is only ~10 Hz bandwidth and Y motion is intentionally slow, trading loop bandwidth for higher effective resolution via low-pass filtering sounds ideal for stable stand-off control.

Given that, THCAD-2 looks like the right solution for the current phase, especially with it coming back in stock shortly.

For any future higher-speed sensor upgrades, I’ll revisit true ADC options like the 7i87 if needed — but for now THCAD-2 + filtering seems well matched to the application.

In addition, I will need extra isolated digital I/O for valves, interlocks, and machine signals. I was looking at the 7I84U isolated remote field I/O card (sourcing/sinking outputs), but it currently shows as out of stock. My preference is to stay within the Mesa ecosystem rather than using generic BOBs, to keep things robust and well-supported in an electrically noisy environment.

If you have any guidance on availability of the 7I84U, or alternative Mesa smart-serial I/O options that integrate well with 7i96S for isolated field I/O, I’d really appreciate your recommendation.

Thanks again for the detailed clarification.