[Quazar]

Count me in.

I looked on my C4 and it has the same chips and the following numbers on the board. I did not trace it all out though.

On a sticker
A-4 SN:A2007060269

Painted on board
SMS0462CG

Etched? into board
S0462CGA

Is this one single board, or two boards (one for the LCD and one for the buttons)?
The pic chrhinna posted of the C6 panel looks like it has a single board.

If you could post a picture of what the board looks like, that would be helpful. Attached are front/back photos of the ones from my SX3. The important bit is going to be the 10-pin connector labeled CON2, which is the interface my board attaches to. If that is different, it won't "just work".

There may also be protocol differences, but that isn't going to become clear till we try. If you are willing to (carefully) take some readings with a voltmeter, we can figure out if the connection is at least electrically similar to the SX3.

Also, can you provide a few details about your C4 so I can make sure the software properly accounts for the different drive ratio. In particular, I need to know what the min/max RPM range is (not the rated speed, but the range the controls will actually let you set). And how much the RPM changes each time you click + or -.

If you know the exact drive ratio, that would be great too. For instance, on the SX3, the motor has a 22-tooth timing pulley, and the spindle has a 45-tooth.

Cheers,
- Dean

[compunerdy]

It does have the connector but it is one board. Here is a pic and I can take any voltage readings you need me to.

[Quazar]

Very good picture - it tells me quite a lot. I was able to verify several of the traces, and I didn't find any wiring differences. It certainly looks like it might be compatible.

Here are a few readings I would expect to see if the connections are the same. They all use the purple wire (2nd from the top) for the black (-) test lead.

• Red wire should read about +5V
• Black and Yellow should also read about +5V (maybe slightly less)
• Orange, Blue, and Green should produce indeterminate reading between +0.5V and maybe +4V
• Brown, White, and Gray are unused on my board, so I don't have any test for them.

The one thing I do see that is slightly different is the 10-pin connector itself. The connector on yours looks like a JST connector whereas mine is a CH2.5 connector.

This is just a matter of picking the right connector to solder onto the interceptor board - can you see what the connector on the other end of the 10-wire cable looks like?

Cheers,
- Dean

[rwskinner]

I'm sure interested in what you come up with for the SX3 spindle control Quasar. I can tell I will miss having spindle control on the mill like I do the lathe.

I finished up all my limits and got the SX3 up and going. It seems to work great and the limits/home switches are very repeatable. I used Honeywells for the X & Y and used a Micro for the Z home, all in NC Series circuit. Worked great.

What kind of backlash are you guys seeing out the the SX3 Deluxe kit? I was seeing .006" on the X & Y and 0.010" on the Z. I have adjusted and tweaked my ars off and the best I can do on the X&Y is now 0.0025" and I still haven't got any better on the Z which is still 0.010".

BTW, I have the latest screw for the Z which has a jam nut and threads.

I know 2-1/2 thousands isn't much to really worry about, but I'm almost that good on my lathe with cheap ball screws and single circuit ball nuts so I was really curious to what you all have seen to be the norm.

CR - The 2.1 to 1 ratio I'm running on the Z seems plenty fast to tell the truth. I saw in a previous thread you mentioned there wasn't enough room for that ratio on the SX3.

[rwskinner]

Quasar, since your interface board is simulating button presses, are you seeing the same slow, sluggish control and response the Syil KX3 does?

What I mean by that is RPM control taking a long time to reach the desired speed or not controlling it very well.

I know the timing is important because it looks like their Xmit piggy back board has the Atmel multiplexing the buttons, so it's like push a button and wait for it to respond then push and wait....

I'm wondering how hard it would be to get rid of the Atmel all together and control the motor circuit directly? I have to look closer at the board and chips and see how they are controlling the BLDC motor.

Richard

[Quazar]

Quasar, since your interface board is simulating button presses, are you seeing the same slow, sluggish control and response the Syil KX3 does?

I am using an algorithm that attempts to hit the target speed by (1) knowing the current speed, (2) figuring out how many button-scan-times to hold down the virtual button, (3) checking the speed afterward to ensure we are close, and then (4) dial-it-in 10RPM at a time with individual clicks.

The software is still in its infancy here, but initial experiments usually hit pretty close to the target speed on the first try.

I'm wondering how hard it would be to get rid of the Atmel all together and control the motor circuit directly? I have to look closer at the board and chips and see how they are controlling the BLDC motor.

I thought about that and even tried to read the firmware from the ATmega168, but the security fuse was blown so no luck. It should certainly be possible for somebody with enough information to "chip" the control board and then rewire the cable from the operator interface to a CNC BOB.

If I had more experience with BLDC motor control, and more details of the driver board, I'd consider trying this approach. But without that, the button interposer approach is safer and I'm fairly confident I can get it to work well enough.

Cheers,
- Dean

[rwskinner]

I don't have the exact link, but the Atmel site happens to have an application note for the Atmega controlling a BLDC motor. I would almost bet you could trace the pins of the current chip for the hall effects and windings and configure the new Atmega with the BLDC Code. Then customize away from there. My mill is together right now and I can't remember if the main controller board had the chip soldered or socketed. I do remember the KB interface daughter board was all socketed.

Let dig around, I think I saved a copy.
Ah, here is one of the links:

http://www.atmel.com/dyn/Products/to...p?tool_id=3764

[Quazar]

I don't have the exact link, but the Atmel site happens to have an application note for the Atmega controlling a BLDC motor. I would almost bet you could trace the pins of the current chip for the hall effects and windings and configure the new Atmega with the BLDC Code. Then customize away from there. My mill is together right now and I can't remember if the main controller board had the chip soldered or socketed. I do remember the KB interface daughter board was all socketed.

Let dig around, I think I saved a copy.
Ah, here is one of the links:

http://www.atmel.com/dyn/Products/to...p?tool_id=3764

Yea, I spotted that a while back, but that is for a purpose-made BLDC controller. The part on the SX3 control board is a generic microcontroller with some custom firmware in it, so this appnote doesn't apply (beyond basic concepts). I did trace out most of the lines on that board, and it is pretty much exactly what you would expect (3 high-side drivers, 3 low-side drivers drivers, 3 hall sensor inputs, optoisolators for all, etc).

I have no doubt somebody could go and "clean room" some compatible firmware with a CNC-friendly interface, but that isn't my goal at the moment. If you would like to have a crack at it, go for it! I'll be happy to compare notes and try out whatever you come up with.

Cheers,
- Dean

[rwskinner]

Ah, I found the pictures. The large board "driver board" is only the power supply, relays and drivers. The small daughter card with the Atmel is doing all the control. Looks that way from the picture. Too lazy to take mine apart right now (Bolted to a big steel bench).

[tsescrl]

Hello,
We are a CNC friendly little group here in Belgium europe)and we work also for remote the SX3 spindel brushless motor an we have an interest in your post.

We attach "ATT00024.pdf" file with all schématic off the brushless drive "XMT-DRIVER-1000" and the control panel.(some working day to obtain it...)

The "On-Off-Spindel-SX3 .pdf file " is our end test for START and STOP the spindel with a one shot system placed after a relay actioned by Mach3, and it work very well.

In this moment, you can use "+" "-" touch to change manualy the RPM off the spindel.
Remember after the first RPM choise, (exp:1000RPM), and push on STOP, if you retart, the RPM recome automaticaly to 1000 RPM.

We are now in reflexion for look 0-10 volts from Mach3 and remote the driver off the spindel and we have differents ideas, normely, 2-3 week, we expect a good solution.
We expect come with a little rock for this big construction.
In some day, we add some page on our little site about SX3 retrofit on http://www.a2p.be.

Alain - Patrick - Patrick - Claude.

[Crevice Reamer]

What kind of backlash are you guys seeing out the the SX3 Deluxe kit? I was seeing .006" on the X & Y and 0.010" on the Z. I have adjusted and tweaked my ars off and the best I can do on the X&Y is now 0.0025" and I still haven't got any better on the Z which is still 0.010".

I know 2-1/2 thousands isn't much to really worry about, but I'm almost that good on my lathe with cheap ball screws and single circuit ball nuts so I was really curious to what you all have seen to be the norm.

CR - The 2.1 to 1 ratio I'm running on the Z seems plenty fast to tell the truth. I saw in a previous thread you mentioned there wasn't enough room for that ratio on the SX3.

Are you using helical couplings on X and Y? The Z belt needs to be really tight to eliminate backlash. There is probably not enough adjustment with 2:1 pulleys to get the belt tight enough. Try the 1:1 pulleys and see if backlash improves with tighter belt.

CR.

[rwskinner]

Yes, Helical zero backlash couplings on X&Y. I did not tighten the belt very tight as I was afraid to put too much side load on the stepper bearings.

I don't have another pulley set to try at the moment. What are you seeing for backlash on your mill CR?

Richard

[Crevice Reamer]

Yes, Helical zero backlash couplings on X&Y. I did not tighten the belt very tight as I was afraid to put too much side load on the stepper bearings.

I don't have another pulley set to try at the moment. What are you seeing for backlash on your mill CR?

Richard

I have almost zero backlash. I did have a lot on Z before tightening belt to the max, now practically nothing. Stepper bearings are MADE for radial load. Tighten up that belt.

You should not have that much table backlash with helicals and deluxe kit. Are they CNCFusion helicals?

CR.

[Quazar]

We are a CNC friendly little group here in Belgium europe)and we work also for remote the SX3 spindel brushless motor an we have an interest in your post.

Excellent. I'm just about to order my first prototype boards, and then I'll be getting the software put together. I'll share my work as I make progress.

We attach "ATT00024.pdf" file with all schématic off the brushless drive "XMT-DRIVER-1000" and the control panel.(some working day to obtain it...)

This would be tremendously helpful, but I don't see an attachment. If you could post that, I would very much appreciate it.

The "On-Off-Spindel-SX3 .pdf file " is our end test for START and STOP the spindel with a one shot system placed after a relay actioned by Mach3, and it work very well.

In this moment, you can use "+" "-" touch to change manualy the RPM off the spindel.
Remember after the first RPM choise, (exp:1000RPM), and push on STOP, if you retart, the RPM recome automaticaly to 1000 RPM.

This is a good start. I am hoping to have full 0-10V speed control without the user having to press any buttons, but the software still has a way to go before I achieve that.

We are now in reflexion for look 0-10 volts from Mach3 and remote the driver off the spindel and we have differents ideas, normely, 2-3 week, we expect a good solution.
We expect come with a little rock for this big construction.

I'm afraid I don't understand this last sentence.

In some day, we add some page on our little site about SX3 retrofit on http://www.a2p.be.

Alain - Patrick - Patrick - Claude.

Thanks for the post - I'll keep watching your website to follow your progress.

Cheers,
- Dean

[Quazar]

Several people have commented or asked (both on- and off-list) about other design approaches for this project, so I thought I'd write up a quick post to show my thought process in selecting my current approach.

These are the designs I considered, and the pros and cons of each. Also, keep in mind that this analysis was influenced by my skills, experience, and specific goals (G540), so other folks may reasonably reach a different conclusion from the same analysis.

1. Replace BLDC Drive. To do this, I would remove all the electronics from the SX3 bay and simply replace them with an off-the-shelf BLDC motor drive. This is the most invasive (and expensive?) approach, but would probably yield the best results. This would not allow the front panel controls or display to work, but it would provide very reliable and accurate speed control. Also, without exact details on the motor, there may be some difficulty selecting an appropriate BLDC drive (I have never attempted such a pairing before, so my educated guesses here are not very educated).
   
   
2. Replace the firmware on the control chip. The small control board that is plugged into the BLDC Drive board contains a standard ATmega168 microcontroller. It should be possible to program a new chip and plug it in there. I have never written software to drive a BLDC motor, nor do I have any specs on the drive electronics. In particular, it seems like not knowing the timing details could lead to an unreliable device (I don't want to burn out the BLDC Drive board). Even if I took this approach, I would still need some additional circuitry to divide the 10V signal down into the 5V analog input range of the microcontroller, plus wiring for the RUN/DIR signals. The positives of this approach are that it is probably the cheapest option, and it could provide very quick speed changes if I got the BLDC drive logic just right.
   
   
3. Replace the control board. This is much like #2, except instead of just replacing the chip, I would replace the entire daughterboard with a new PCB. The main drawback here is that it is all the work of #2 PLUS there are a lot of additional parts on that board that would have to be duplicated onto my board. This would be a somewhat risky approach (more work, more unknowns) but it could provide excellent results in a compact and easy to install design.
   
   
4. Intercept the signal between the control board and the operator interface. This is what I am actually doing. The downside is that I get less exact control over the motor, since I can only simulate button presses. On the plus side, I can leave the complexities of driving the BLDC motor to the existing controller that already knows how to do that. This design does not require dealing with high energies, so it keeps everything safely in the realm of digital electronics (where I am comfortable).
   
   
5. Replace the operator interface board. This would be similar to what I'm doing with #4, but rather than inserting a new board along the cable, replace the existing button board. This would simplify a few aspects of the design. On the downside, it would more than double the board size, which would drive costs up. Plus, it would put the CNC connections in the mill head, which is not a very convenient place for them.

In the end, I opted for #4 for the following reasons:

• I knew I could handle all the required tasks
• It is probably the second cheapest option (my arbitrary target was US$50)
• It is unlikely to cause damage to the SX3 because (barring a wiring fault) it can only do what is already possible via button presses.
• It keeps the front panel controls and display operational (I view this as a plus)

The biggest risk with this approach is that it may not be able to change spindle speeds as quickly as we would like. I am still hopeful that what I can achieve will be quite good.

Cheers,
- Dean

[compunerdy]

Sounds like the right game plan to me.

[cjdavis618]

#4 is what Sieg did in the beginning with the SX3. Neil from here at the board would know the most about that interface between the 2 components. I think he converted his Sieg SX3 to the X4 controller. If they would just make the X4 componets availible to the public, that would help alot.


If I remember right, the switch on the front set it from manual and CNC mode. then the board took over the rpm settings but was very slow in getting the speed right. It created fits with those that change tools quickly due to the dwell timing.

Personally, I would recommend version 5. The reason is that most of us here are creative enough to route cables and work with designs. Plus, the head already has cables running to it on the left side anyway. These conduits could be reused as needed.

[Quazar]

Personally, I would recommend version 5. The reason is that most of us here are creative enough to route cables and work with designs. Plus, the head already has cables running to it on the left side anyway. These conduits could be reused as needed.

I'm curious what is the appeal of option 5 is to you? It doesn't offer any functional advantage over 4. And the conduits would still be full with the existing cables (still needed), so you wouldn't have much room to pull new CNC wires through them.

Here is a quick look at the design as it currently stands:



The PCB measures 3.8" x 2.5". Mounting holes are on 3.5" x 2.2" centers and are sized for #6 or M3 screws

SX3 Interceptor v0.7 sch.pdf

I'd like to thank the forum members that have made suggestions for improvements - I think the design is ready to go, and I'll be getting my first run of prototype boards made very soon. Once I get the boards back, I can start the process of getting the software working on them. After that, I'll have a much better idea of how quickly I'll be able to get the spindle to the commanded speed.

Updates as I go, of course...
- Dean

[cjdavis618]

I mean no disrespect. But my problem with the mill itself is the factory boards unreliable history. I know of many that had issues with thier machines right from the factory with the daughtercard that is on the power supply board.

I myself, have issues every now and again where the machine will turn on and just beep a solid tone and not completely start. That would be after the second time that I have had to replace my main board controller. It is just plain unreliable. I think by getting rid of the factory components (Or at least the ones that fail miserably) we would be better off in the long run and make a better machine from better controls. By no means am I someone that could put the electronics together in that sense, but I would buy them in a heartbeat. After hearing so many horror storys of the Sieg and the "Wait for the eternally long spin up" I would hate to see you get hampered by the faults of the original board designs.

I will try whatever you make, but I am certainly not against ripping all the electronics out of mine to make a much more capable machine than I have now.

[metalworkz]

Hello Dean,
I am very interested in the prospect of returning my SX3 to the computer controlled state that it was in before the display got shorted. I had one of the earlier spindle boards and did not experience the slow build up to the required speed that the later boards reported. Since the display shorted I have turned my mill into the Frankenmill and added a single speed motor to the top of the Z that enables low RPM for steel and metal work and a Craftsman(rotozip size)
spindle to the side of the Z for cutting wood and similar materials at higher RPMs. While this is a working alternative it would be great to turn the spindle on and off through the software and control flood coolant also without being in attendance. I will be watching to see the outcome of your great work with this and would be interested in a reasonably priced alternative.
Regards,