[Mike4703]

Doorknob--there is no DB25 ouput on the breakout board that is attached to the controller. That big off white cable multi pin cable goes to the pendant controller. As far as I can tell it is not a standard output--There is no pinout in the documentation that came with it, and there is no reference to using a computer printer port. The breakout board is the only hookup to the pendant controller that I am using in place of a direct computer connection. There is only +5v, pulse, dir, and shield outputs for each axis. I will try some probing with the scope as you suggest and see what I can figure out.

[doorknob]

Doorknob--there is no DB25 ouput on the breakout board that is attached to the controller. That big off white cable multi pin cable goes to the pendant controller. There is only +5v, pulse, dir, and shield outputs for each axis.

That's what I don't understand - the TB6560 board already has "breakout board" functionality built in to it. So, using another breakout board in between the pendant controller and the TB6560 board would seem to be redundant, unless the breakout board is being used for some other purpose, such as adapting the pinouts of the pendant controller to the input pin layout of the TB6560 board, or accessing certain pins or functions of the pendant controller that can not be accessed through the TB6560 board.

You say, There is no pinout in the documentation that came with it, and there is no reference to using a computer printer port.

My interpretation of that statement is that you are using the breakout board to perform pin mapping from the pendant controller to the TB6560 board. Why couldn't that be done with a simple "patch panel" arrangement, unless there is some other need to buffer or voltage-translate the output of the pendant controller to make it compatible with the input to the TB6560 board?

[a1cypher]

Thought you all might be interested in seeing my results with the 3axis TB6560 board.

Attached are photos of my first try at milling a PCB. I am very happy with how it turned out.

The traces are designed to be 12 mil, although they may have been reduced slightly if my cut was off a bit. For alignment, I first milled a flat surface in a piece of MDF which is bolted to my larger spoil board. I then drilled the four corner mounting holes with a bit that is roughly the same diameter as a paperclip. Then I milled out the small blank from a larger sheet of copper clad. Next I drilled the same four holes on my milled flat spoil board and then used double sided tape and four paperclips for alignment. Next I milled and drilled top, then flip board re-align with 2 paperclips and mill bottom.

You'll notice some slight alignment issues on the reverse side but it is still close enough that it should work well. Also, you may notice on the top layer a couple of pads that got cut by the drill. this was not the CNC drill; I didnt have the depth deep enough to go all the way through on some drills so I had to go back and punch them through with a dremel. Messy me hit the surface in a couple spots cutting two traces.

The milling bit I used was a cheap 60 degree V bit from ebay. I got a back of 10 of them for about $20 shipped. The same bit was used for the entire board and it looks like I should be able to get at least a few more out of it. Also, I cut the board at 20ipm which I think is a fairly fast speed for this scale of work, so I am quite happy.

Also, if you're interested, I'm using a Fireball V90 CNC with a Paul Jones 3-speed original spindle. Both of which I am very happy with so far.

Cheers.
A1cypher

[mmcp42]

very neat alignment trick
I may be forced to "borrow" it for mine when the time comes!

board doen't look to obad
did you drill with the same machine?

[a1cypher]

yup.. drilled with the same machine using some more cheap bits off ebay. Upon closer inspection, the backside was milled a bit too deep so some traces are quite thin, but I think it should work.

The way I set the zero for milling is to put my multimeter on the spindle and the copper and then lower it until I get the beep starts. Then I raise it back off until it stops, and lower it just enough that it starts again. Worked well on the top, but I guess I didnt put enough effort into it on the back side.

[Mike4703]

That's what I don't understand - the TB6560 board already has "breakout board" functionality built in to it. So, using another breakout board in between the pendant controller and the TB6560 board would seem to be redundant, unless the breakout board is being used for some other purpose, such as adapting the pinouts of the pendant controller to the input pin layout of the TB6560 board, or accessing certain pins or functions of the pendant controller that can not be accessed through the TB6560 board.

You are right, there is probably is redundancy between these two boards, the one from the pendant controller only has the outputs that I previously mentioned. The cable from the controller to the board is a custom 50 pin job.

You say, There is no pinout in the documentation that came with it, and there is no reference to using a computer printer port.

True

My interpretation of that statement is that you are using the breakout board to perform pin mapping from the pendant controller to the TB6560 board. Why couldn't that be done with a simple "patch panel" arrangement, unless there is some other need to buffer or voltage-translate the output of the pendant controller to make it compatible with the input to the TB6560 board?

The board is part and parcel of the contoller, it's not my choice. There must be some place on the TB6560 board that I can interface this to though. All these devices use the same logic signals. But other than the optoisolators and the 74HC14 there isn't much inbetween the TB6560 chip and the DB25 port inputs--what am I not understanding?

So far I've scoped the clock output on the pendant x axis and it looks like a text book square wave. I'll post some when I have time to work on this again.

[Mike4703]

doorknob-
Ok, I was going to try and get better pics--remember I'm using a inexpensive handheld scope with no computer output, but this is clear enough. The scale is 50 millisec/division and 0.4v per division.

[doorknob]

doorknob-
Ok, I was going to try and get better pics--remember I'm using a inexpensive handheld scope with no computer output, but this is clear enough. The scale is 50 millisec/division and 0.4v per division.

OK, I have a better understanding now.

Can you verify for me that you have connected the scope input to the X-axis step output of the breakout board?

It's a bit hard to see in the photo, but it appears to me that your scope is set up for 50 microseconds/division (not milliseconds).

It looks like the waveform is approximately 1.0 volt peak-to-peak. (I am guessing that the scope input is DC-coupled, and that ground level is at the bottom of the square wave - is that the case? I'm also guessing that you are using a 1X scope probe and not a 10X probe.)

The TB6560 board's step input will probably not work with that low a voltage on its input. The step input goes to a 74HC14 Schmitt trigger section. If I am interpreting the 74HC14 datasheet correctly (http://www.nxp.com/documents/data_sheet/74HC_HCT14.pdf), looking at the "transfer characteristics" in Table 10 on page 8, when running the 74HC14 from a supply voltage of 4.5 volts, the minimum positive-going input threshold voltage is shown as 1.7 volts, but you would be safer with something higher than that (the range for that threshold is shown as 1.7 volts to 3.15 volts). So I doubt that the step pulse is making it through the 74HC14, which means that it is not making it through the optoisolator to the TB6560 (or to the second 74HC14, if you've done the board modification).

Can you verify the power supply voltage that the breakout board is powered from? I'm surprised to see that the step signal voltage is that low.

[H500]

Also got an ocilloscope, a $224 HPS10 handheld from Vellman.

You should have bought the Rigol 1052e scope instead. It's a color 50Mhz, 1Gs/s dual channel scope for $100 more.

[aarggh]

You should have bought the Rigol 1052e scope instead. It's a color 50Mhz, 1Gs/s dual channel scope for $100 more.

Actually if you buy the 1052 you can do a simple hack to turn it into the 1102 model, as the 100MHz and 50MHz models are the exact same model, just different firmware!

[Mike4703]

H500-Thanks, I should have posted on here before buying my scope.

However in the process of trying to set up the limit switch for the Z axis I had some alligator clip jumper wires hooked up to test it and one jumped loose and because my TB6560 board was out of the enclosure and sitting propped up, the clip touched something and immediately fried the board. I'm talking smoke and fire. I removed the chip that fried and tested the other axis but it's dead. I am giving up on this board at this point and have ordered some Gecko G251X drivers. I still have the issue of the pendant controller only putting out 1v step pulses. .. By the way I tested the little blue manual controller that connects to the TB6560 DB15 and it still puts out good pulses. What about isolation between the pendant controller and the Gecko drives? I can't afford to toast anymore boards.

Doorknob--I can confirm all your deductions about my setup in your last post,I checked the MO-CON501 interface board for supply voltage (see earlier post ) and it has 5v like it's supposed to. Sounds like this will still be a problem driving the G251X also as it calls for a minimum pulse amplitude of 3v. Since this morning I've recieved the drives and set up a test, and that little blue manual controler works with the Geckos also. I hooked my scope up to it and there are very narrow downward square wave of about 4v on the step terminal. When optimally adjusted, the stepper is spinning many times faster than it did with the TB6560 board. Not getting a direction change though. The dir terminal shows +4-5v no matter which direction button is pushed.

I probably should move to another thread, since I'm no longer fixing the TB6560, but where?

[H500]

The dir terminal shows +4-5v no matter which direction button is pushed.

It sounds like the dir pin might be fried also. Did you try all axes?

[doorknob]

I still have the issue of the pendant controller only putting out 1v step pulses...

Not getting a direction change though. The dir terminal shows +4-5v no matter which direction button is pushed...

I probably should move to another thread, since I'm no longer fixing the TB6560, but where?

It might be a good idea to start a new thread here in the General Electronics section of the forum.

To correct the 1-volt step pulses, you could put together a small interface circuit (for example, you could probably use something like an LM339 comparator IC: http://www.national.com/ds/LM/LM339.pdf)

But a better idea might be to use your scope to back-trace the circuitry of the breakout board to see if you can figure out why the step pulse voltage is so low. You might have to do the same kind of diagnostic work anyway to figure out why the direction signal is not changing. If you can see all or most of the circuit board traces on the breakout board, and can perhaps identify some or all of the integrated circuits and other active or passive components on the board, then you can put together a schematic of sorts which should help you in the troubleshooting.

(I'm not certain from your description which direction terminal is stuck at 5 volts - is that terminal on the little blue manual controller box or on the breakout board?)

[Mike4703]

Doorknob-
The dir change problem is with the little blue controller that comes with the TB6560 board. I am using it as a step and direction source for setting up the new Gecko drivers. Sorry for the confusion. No problem though, I just remove the wire from the dir terminal input on the Gecko board and it changes direction like it should. Good enough for a test. Be nice to get it working, as this is the simplest way to move the axis and I am understanding that moving the axis manually while hooked up to the driver board is a good way to fry it. Sherline makes this real easy because all the motors have handwheels on them.

Thank You for your interest and advice--I will continue with a new thread in General Electronics.

[paul langwade]

I built a small testbed machine to get my head around some of this CNC stuff before hopefully building a serious one. I bought the 3 axis tb6560 board on ebay and predictably it exhibited all of the weaknesses discussed here.So I changed out the caps to 100pf, cut out the motor idle bit of the circuit, bypassed the step optos and ran another 12v fan in series with the existing directly off my 24v supply. Hey presto my little machine is running as well as I could expect from this driver design and I am now able to experiment with all kinds of mechanical/electrical/software options. Thanks to all those who laboured over discovering the shortcomings in the design. You saved me alot of time and frustration.

[GrootWitBaas]

Hi Paul, Nice to hear a susses story

[drmacro]

Has anyone ever figured out why they have pull-down resistors all over this board?

The doc for the IC clearly shows there are internal pull-downs on all inputs.

And, 6.8M from collector to ground on many of the optos and bipolars what's that for?

Mac

[strykerg]

hi, i just read the first post so forgive me if i am repeating anything/anyone.

i just got me one of these chinese boards and also had issues:

i was getting extra steps, if i left axis move from say 0 to 100 and left them for some time, i would come back and actually find them moving at -2 to 102. as you said the prob is the ic's input signal shouldn't be driven by an opto (why are the optocouplers there anyway? at least they could'ave been at the input) so i bypassed all the clock optos.

i was still having problems after this, but this time with missed steps, and realized what the problem was: when changing direction the (optocoupler driven) direction pin did not change fast enough as the first clock cycle, so the first clock cycle was being in the wrong direction! i bypassed also the direction opto's and all my problems were solved.

i attached pics of the various signals with/without optos

hope this was helpful for anyone

[interzis]

Interzis, All,

After extensive research and modification to my control boxes (two machines) I was able to solve ALL my TB6560 problems. Please follow my instructions below to the letter and I guarantee you'll have the same success...

1) Remove TB6560 from machine
2) Install Gecko G540

All problems with the TB6560 solved. By the way I still have two boards for sale if anyone wants one of the pieces of Cr@p...... They're fine for woodwork that you can reset zero after each piece, but metalwork is HIGHLY NOT recommended. I snapped more carbide bits and ruined more parts than the cost of 10 geckos... They are WELL worth the price to work WITH your machine and not ON it.

Cheers,
Jeff

Many thanks Jeff! All my problems are now history!
I just installed my new arrived G540 and it seems to have another machine!
No missing steps, no extra steps, no disturbing hissing noise, NO PROBLEMS!

Guys, if you want just to play in the world of CNC, use a TB6560 board!
Otherwise, use something else.

I don't intend to make some advertising for Gecko's products but after changing TB6560 with G540 my machine's G0 was increased from 1000-1200 mmpm to 6000 mmpm and no one step is missing.

Kind regards,
Seb

[julien_lyon]

Hello, I'm new on this forum.
I would like to buy a 3 axis stepper controller TB6560. I have seen that this board must be supply between 12V and 36V but, my 3 stepper motors are 5V only.
Is it possible to supply this board with 5V only ?
Thank to all for your responses.