[ShreddinPB]

A few observations...

The oscilloscope traces back in post #1 show the signal on pin 3 of the TB6560 as normally high, with a negative-going pulse. It also shows a pulse width of perhaps 60 to 80 uS.

Thats the way mine was before the modification.. I thought since the mod I did only had one inverter that is how the signal should be now

That differs from your scope traces, which show a normally low signal on pin 3, with positive-going pulses. I'm not sure whether I'm reading your scope settings properly or not, but the pulse widths from Mach3 and from your blue pendant appear to be of shorter duration.

something to note about that, when I use the blue pendant, its max speed isnt nearly what it is when I use the USB/Mach3.. its about half as much

You do need to be sure, however, that your oscilloscope settings are not somehow inverting the displayed signal. When you connect the probe to a ground point on the board, do you see a flat line at the bottom of the screen?

I cant find any setting that does that at all.. its a MS0-19 usb oscilloscope. Yes there is a flat line at the bottom of the screen when I connect the ground.

Since you are following the OP's modification instructions, it might be best for your settings to match his (for example, the function of the 'activity' LEDs on the board likely expects a signal matching that used by the OP).

Does your blue pendant have a way to specify the polarity of the pulse?

I dont think so.. it has some pots on it but thats it

Have you tried disconnecting the blue pendant, then setting Mach3 to Step Low Active = Green and seeing if Mach3 will turn the motors with that setting (in order to see if Mach3 will work in that mode without fighting against the blue pendant)? For these preliminary tests, it's best not to test with both Mach3 and the blue pendant connected at the same time, because you want to avoid possible interactions between the two separate methods for controlling the TB6560 when you're doing your tests.

I get nothing if I set Mach3 to Atep Active Low = Green.. no movement and no pulse at pin3
I dont have them both plugged in, I did test that and it doesnt work, when they are both plugged in, the Z axis on the blue will only move in one direction no matter which + or - you push

I don't know of any reason for suspecting that your USB pendant is somehow affecting the signals from your parallel port, but if you're monitoring the signals with your oscilloscope while you manipulate it, then something else is happening. There are a number of other factors that could be limiting your top motor speed, including the settings of the DIP switches on the board. You can reach a state where for the given motor drive settings that you are using, you will exceed the capabilities of the motor to follow.

my DIP settings are
off on off on on on

[doorknob]

Then I don't understand why the polarity of your step pulse is different from that shown in post #1. You could determine that by following the polarity of the pulse at each location where it is affected by the circuit, from the input, through the inverters and optoisolator to the step pin, both with Step Low Active set to Green and also set to Red. That should permit you to figure out why it doesn't work and you don't get a step pulse on pin 3 when set to Green. But to do that you would have to be able to understand and follow the schematic, and it would be helpful to know some basic electronics in order to make sense of what you are seeing and why you are seeing it.

The TB6560 step pin does not trigger based on the polarity of the step pulse directly, rather it is triggered by a rising edge of the pulse, whether that rising edge occurs at the start of the pulse or at the end of the pulse.

The step pulse width should not affect the speed of the motor (although there is probably some minimum acceptable pulse width for the circuit - I just don't remember what the spec calls for). However the step pulse repetition rate does directly affect the speed of the motor. Your scope traces do not show what that timing is, for either the Mach3 pulses or the blue pendant pulses. It may be that the pulse repetition rate from the blue pendant can not be set as high as that of Mach3.

I have not yet studied the DIP switch settings in any detail, other than to note that the current through the motor windings is set by two of those switches (in conjunction with other component values), and I guess that some other settings are related to current decay patterns and microstepping, but I simply haven't focused on any of those so far.

[leaveme]

The best deal would be to bypass the opto for step signal and connect on-board buffer output directly to the clk pin at tb6560. This is what I'm using for all of my boards (3 at the moment) and works brilliantly.

The board is not realistically isolated so I don't see the point to use this opto.

[ShreddinPB]

The best deal would be to bypass the opto for step signal and connect on-board buffer output directly to the clk pin at tb6560. This is what I'm using for all of my boards (3 at the moment) and works brilliantly.

The board is not realistically isolated so I don't see the point to use this opto.

Sadly I dont know how to do this lol

[ShreddinPB]

Then I don't understand why the polarity of your step pulse is different from that shown in post #1. You could determine that by following the polarity of the pulse at each location where it is affected by the circuit, from the input, through the inverters and optoisolator to the step pin, both with Step Low Active set to Green and also set to Red. That should permit you to figure out why it doesn't work and you don't get a step pulse on pin 3 when set to Green. But to do that you would have to be able to understand and follow the schematic, and it would be helpful to know some basic electronics in order to make sense of what you are seeing and why you are seeing it.

The TB6560 step pin does not trigger based on the polarity of the step pulse directly, rather it is triggered by a rising edge of the pulse, whether that rising edge occurs at the start of the pulse or at the end of the pulse.

The step pulse width should not affect the speed of the motor (although there is probably some minimum acceptable pulse width for the circuit - I just don't remember what the spec calls for). However the step pulse repetition rate does directly affect the speed of the motor. Your scope traces do not show what that timing is, for either the Mach3 pulses or the blue pendant pulses. It may be that the pulse repetition rate from the blue pendant can not be set as high as that of Mach3.

I have not yet studied the DIP switch settings in any detail, other than to note that the current through the motor windings is set by two of those switches (in conjunction with other component values), and I guess that some other settings are related to current decay patterns and microstepping, but I simply haven't focused on any of those so far.

It looks to me like its inverting inside the 74hc14..
I tested at the cable connector, at the 74hc14 input, at the output, and at pin 3..
The pulse going into the chip is the same as at the connector, and the output of the chip is reversed just like at pin3..

are there different 74hc14 chips that do different things? This is the one I got
Digi-Key - 568-1402-5-ND (Manufacturer - 74HC14N,652)

[GrootWitBaas]

No they are the same. sorry I have not answered before now, was not following. I should mention I have also swapped the opto "in/out" for all 4 axes. This might be the problem you have seen. the 10k's(103) should be fine for the resistors. My dip switch settings is all on except for 2 that is off. Hope this helps. I posted a photo of my board instead of a schematic, they say a picture says 1000 words.

Ok marked is the 4 opto isolators where I swapped the in/out if you can call it that. bascaly just the two pins on one side is swapped around and isolated with small piece of head-shrink tubing. Also my dip switch settings is shown.

Groot

[doorknob]

I'm not really able to figure out your latest oscilloscope traces. Were they done with Step Low Active set to Green or to Red?

I don't see any pulse in the first image. So maybe there's a problem with the oscilloscope settings in that shot.

The 74HC14 is intended to invert the input signal while "cleaning up" the pulse. Each 74HC14 package has 6 inverters inside.

According to the Version 2 schematic in the OP, there are actually two 74HC14s in the signal path between the parallel port input and pin 3 (one of them is built in to the board), as well as an optoisolator.

So my suggestion for diagnosing the problem with the unexpected behavior with Step Low Active set to Green was intended to capture the pulse at every point in the signal path where the signal goes through a device. That way you can follow each signal inversion or buffering along the path - but you really need to refer to the schematic in order to accomplish that. Then if you can repeat the exercise with Step Low Active set to Red, you can possibly see where the signal is lost or otherwise is doing something unexpected. Without that, you're just guessing at what's happening.

[leaveme]

Sadly I dont know how to do this lol

This is what I did:

1. Cut the line to bypass on-board opto-isolator.
2. Jumper between on-board buffer output and driver IC.
3. Cut the line to disconnect the non-spec circuit (as it is described by Lasik, but it is optional).

[ShreddinPB]

This is what I did:

1. Cut the line to bypass on-board opto-isolator.
2. Jumper between on-board buffer output and driver IC.
3. Cut the line to disconnect the non-spec circuit (as it is described by Lasik, but it is optional).

Is this all you did.. or did you do the 74hc14 also?

[ShreddinPB]

I'm not really able to figure out your latest oscilloscope traces. Were they done with Step Low Active set to Green or to Red?

red.. i'll try green now

I don't see any pulse in the first image. So maybe there's a problem with the oscilloscope settings in that shot.

no there was no pulse.. just showing a baseline I guess

The 74HC14 is intended to invert the input signal while "cleaning up" the pulse. Each 74HC14 package has 6 inverters inside.

According to the Version 2 schematic in the OP, there are actually two 74HC14s in the signal path between the parallel port input and pin 3 (one of them is built in to the board), as well as an optoisolator.

So my suggestion for diagnosing the problem with the unexpected behavior with Step Low Active set to Green was intended to capture the pulse at every point in the signal path where the signal goes through a device. That way you can follow each signal inversion or buffering along the path - but you really need to refer to the schematic in order to accomplish that. Then if you can repeat the exercise with Step Low Active set to Red, you can possibly see where the signal is lost or otherwise is doing something unexpected. Without that, you're just guessing at what's happening.

more testing on its way lol

[leaveme]

Is this all you did.. or did you do the 74hc14 also?

This is all I did.
Additionally I replaced the osc capacitor to 100pf.

[ShreddinPB]

Im about over this thing hahaha I wonder if there is just a way to limit the speed in mach3..
I did the swap at the optoisolators also

The pulses look right at the cable. I havnt spent the time yet to trace the whole way.. but with active low set to green, the pulse is gone before it gets to the 74hc14

[AssassinXCV]

Does anyone know if these problems exist on the 4-axis 3amp version? I just about ready to buy a driver board for my almost complete cnc machine, and i'm having a hard time deciding whether to purchase one of these boards, or the HobbyCNCPro Driver board. I dont feel that my machine (6" x 6" x 6" cutting area) is of need for a Gecko driver, considering it's also 3 times the price of one of these.

Please, can someone help with the decision? I'm going to be using EMC2 to control my machine.

[qld]

Does anyone know if these problems exist on the 4-axis 3amp version? I just about ready to buy a driver board for my almost complete cnc machine, and i'm having a hard time deciding whether to purchase one of these boards, or the HobbyCNCPro Driver board. I dont feel that my machine (6" x 6" x 6" cutting area) is of need for a Gecko driver, considering it's also 3 times the price of one of these.

Please, can someone help with the decision? I'm going to be using EMC2 to control my machine.

Yes the 4 axis board has the same problems, i have one. But the problems are fixed when you make the mods to the board suggested on this forum. cheers

[AssassinXCV]

I dont understand how these are still for sale if there are such big problems with them. If you can't run steppers at a fast feedrate, wouldn't the manufacture-ers find that out during any testing? do you even think they tested the board after designing it? or did they just start building and selling an untested product. i find that it's very un professional to be selling a product with such severe problems when doing the very basic of use.

[Connor]

I have to ask.. I've been using a 4-Axis version of this board for a while now.. I've not made any modes (except to replace a driver chip I blew on my own and a few optos I blew).. and not having any issues. However, I'm running EMC, and my motors are pretty strong for (354oz for X and Y and 287oz for the Z).. What exactly are these mods doing for you guys? I run my X and Y and 1/2 stepping Full power, and my Z at 1/16 stepping at full power.. Can push almost 200in-min on the X and Y (no load just the gantry 1 turn for 10mm) and around 9in-min on the Z (1 turn for 5mm).. My BIGGEST complaint is the awful hissing I get sometimes.. Especially from the Z.. My wife complains about a very HIGH pitched whine from it that I can't even hear...

Thanks, Connor

[Connor]

Somehow it double posted...

[interzis]

I have to ask.. I've been using a 4-Axis version of this board for a while now.. I've not made any modes (except to replace a driver chip I blew on my own and a few optos I blew).. and not having any issues. However, I'm running EMC, and my motors are pretty strong for (354oz for X and Y and 287oz for the Z).. What exactly are these mods doing for you guys? I run my X and Y and 1/2 stepping Full power, and my Z at 1/16 stepping at full power.. Can push almost 200in-min on the X and Y (no load just the gantry 1 turn for 10mm) and around 9in-min on the Z (1 turn for 5mm).. My BIGGEST complaint is the awful hissing I get sometimes.. Especially from the Z.. My wife complains about a very HIGH pitched whine from it that I can't even hear...

Thanks, Connor

I doesn't fully modify my board yet, I've just received the ICs.
But, until now, I just removed the 10k resistors (disabling the feature which reduce current to the stepper motors when the motors were idle) and the speed was raised from 750mmpm to 1000mmpm without loosing steps. I'm using 3Nm steppers with 3A/ph, powered at 24v and TR16x4 screws.

I've made some testing at 1200-1300mmpm but some steps are still loosed.
I'll do all remaining mod's steps in the next days...

The hissing noise was also reduced, not completely, but still reduced.

So, you can test it just removing these 10k resistors. If no difference will occur just undo.

It worked for me.

Thanks

[GrootWitBaas]

installing the 100Pf caps will reduce the hissing sound.

[leaveme]

Hi Conor,

Audible frequency varies person to person, usually lower ages vs olders. Change the oscilator capacitor for TB6560 to a lower value i.e. 100pf and produced frequency will be out of ear range.