[podolskiy]

Hello.
I bought a circuit board that is supposed to drive a 3-axis CNC machine.

I cant find a manual or any kind of documentation on this specific circuit board, however I found similar datasheets. They all use TB6560.

So I am wondering if there is any way I can drive the stepper motor with 12volts that they are rated for, while powering the DC spindle motor that I bought from Zen Toolworks with 24 volts because it runs at desired RPM and has more torque this way.

So I will attach two PDFs that I have and a photograph of the board that I have.
I could not upload the second PDF but here is the name of the file: HY-TB3DV-M_3Axis_Driver.pdf

I AM LOOKING FOR THE ORIGINAL MANUAL FOR THIS BOARD

[doorknob]

I'm not sure of what your actual question is.

Are you asking how to get both 24 volts and 12 volts out of a 24 volt power supply, or something else?

Typically when using a chopping drive such as the TB6560 you can run a stepper motor with a higher voltage than the motor's "nameplate voltage". So you can probably run your TB6560 board off of 24 volts, with no need to reduce that voltage to 12 volts. Do you have a link to your stepper motor specification?

[podolskiy]

Do you have a PDF manual for this board?

[podolskiy]

I'm not sure of what your actual question is.

Are you asking how to get both 24 volts and 12 volts out of a 24 volt power supply, or something else?

Typically when using a chopping drive such as the TB6560 you can run a stepper motor with a higher voltage than the motor's "nameplate voltage". So you can probably run your TB6560 board off of 24 volts, with no need to reduce that voltage to 12 volts. Do you have a link to your stepper motor specification?

Sorry. I forgot to state the main question.
I am looking for a datasheet so I dont accidentally power my circuit board with 24volts for everything and burn my motors.

[doorknob]

I do not have a manual for that driver board.

But again I doubt that you would be burning out your motors by applying 24 volts to a chopper driver board (but it would be good to see the specs of the motor to better understand its capabilities).

[podolskiy]

So you don't have any information about this specific board?

I mean that I can measure everything with a multimeter and use secondary clues about the abilities of this fairly simple circuit board but I would rather not.

As experimentation goes on I will ask another question about the chopper/stepper motor relationship but I cant state it yet.

[doorknob]

You may find someone who has that same board on this thread:

http://www.cnczone.com/forums/genera...y_chinese.html

[OCNC]

So you don't have any information about this specific board?

I mean that I can measure everything with a multimeter and use secondary clues about the abilities of this fairly simple circuit board but I would rather not.

As experimentation goes on I will ask another question about the chopper/stepper motor relationship but I cant state it yet.

Generally speaking, the chopper board will have it's 1) maximum voltage rating and 2) maximum current that it can supply to the motor. 3) The motor that you use has a maximum current rating. 4) It also has an inductance rating that determines the maximum voltage that it can handle at its rated current. This maximum voltage is 32 times the square root of the inductance in millihenries (mH). If your motor has an inductance of say 3.6 mH then the maximum voltage that gives best performance at it's rated current will be (32*(3.6)^1/2) or 61V. In the case of using a driver board that can only supply 36V maximum this motor will be under powered at all voltages including the 36V maximum of the driver board and will not experience excessive motor heating. If you stay within the voltage rating given for the driver board (assuming the proper current for the motor/driver combination) and proper heat dissipation methods have been designed into the board the board should also not overheat. If on the other hand you had a motor that had an inductance of say 0.8mH whose optimum voltage at it's rated current would be 29V then running it at 36V or any voltage higher than 29V would start to cause motor heating that is not contributing to best performance. This heating could then have a short or long term damaging effect on the motor. The board should still be ok (assuming proper current for the motor/driver combination) so long as it has as mentioned before proper heat dissipation methods employed to meet it's specified ratings. Obviously then the final case to consider is the one where you overheat the board itself by applying a voltage higher than it's specification even if it has proper heat dissipation methods in place to handle voltages and currents up to its ratings. If the output current to the motor is above the motors rating but less than the drivers rating then that current will contribute to the overheating of the motor. If it's over the rating of the driver but not the motor then it will overheat the driver but not the motor.

The main thing to understand is that the driver-motor is a system and the two components have to be considered together to get a stable and efficient system.

Chris

[podolskiy]

So today I hooked up my stepper motors, to a control board, than connected everything to a computer with Mach3 installed.

I figured out how to configure pins by playing with the board
Where can I find this information?

The motors are held still when they are not spinning. I don't need this. Motors get very warm from this. I am afraid to burn the motors. Is there any way I can disable this feature in Mach3?

Are there any toggle switches on the board that I need to switch to make this board run better?

I am using small bipolar steppers (sm200-0.22-1-02) , that are wired in pairs, in parallel because this machine uses two lead screws, one on each side, for every axis.

As far as I had noticed, this board that I am using is a product of some Chinese manufacturer that doesn't have a website or clear documentation, but there are many versions of this board that have similar features and have documentation written.

I assume that something can be extracted from this PDF, page 9. My current settings apparently are set at 25% with those dip switches.

[podolskiy]

What pin do I set to make a spindle relay switch on/off.
Maybe the issue is not in pins but in other settings.

I tried using pins 1,15,16,17 to enable the relay.

Something clicks when I power this board. Maybe the relay is for some other purpose on this board. I think that it is not.
Anyways, there is an output for a spindle and I am measuring a voltage across two pins with a voltmeter and getting no reading.

[john-100]

Hi podolskiy ,

if the pins 2 , 3 , 4 , 6 , 7 & 8 are the step and direction signals for the X Y & Z axis

you will have pins 1 , 5 , 9 , 14 , 16 and 17 that could be either the enable signals for the 3 axis or the relay control

as you have tried to control the relay with pins 1 , 15 (input !) , 16 & 17
I'd now check pins 5 , 9 & 14

in the photo of your board it looks like there is only 13 opto isolators

once you have found which pin is the relay control
1 of the remaining 5 pins will be the enable signal for the X , Y and Z axis

as I'd expect 6 opto-isolators will be for the step and direction signals , 5 for the inputs from the limit switches etc , 1 for the relay
and the remaining opto -isolator being a common enable for all 3 axis )

going by the manuals for other TB6560 boards
the connectors next to the relay will be :-

1) a 6 way connector that connects the 5 inputs to
pins 10 , 11 , 12 , 13 and 15
plus the common ground connection for the limit switches and touch
probe etc

2) a 2 way connector that is the connections to the normally open relay
contacts that close when the relay coil is energised
( not a voltage output from the TB6560 board)


John

[podolskiy]

So why all steppers are held in place when they are not spinning and why are they getting hot? I am afraid to experiment with my CNC machine.

[109jb]

The motors can get pretty darn hot and still be normal. When they aren't spinning, they are still supplied power to hold position. That is what they are supposed to do. Some steppers can get so hot that you can't hold your hand on them and again this may not be any problem.

Two motors should not be wired to the same drive circuit. Each should bo on its own driver. You can define more than one driver for each axis.

[SpyderHelix]

It's the nature of the stepper motor - when they are not spinning, the electricity holds them in place so they cannot move via torque - in case you are drilling etc, the table/spindle wont move.
My motors get hot to the touch when sitting, but if you want to keep them cooler and still run the machine, one solution is to estop your machine when it is not in use. This shuts power down to the motors and keeps them cooler. Then when you want to run a program, clear the estop and you are ready to go. (I do this often)
The nature of the motors will make them hot to the touch, and it is not uncommon to only hold your hand on them for a short time before it becomes too uncomfortable to bear.

[podolskiy]

I am almost done setting up my CNC machine.
If I won't end up burning something, I will write about my CNC machine experience in my blog.

I found some programs that control the LPT port.
By toggling different pins I could see where my spindle relay is wired to. (In my case it was pin 14) Than I could also easily map all my limit switches and where they all go to.

The goal of my design is to make everything so there are no unreplaceable, hard to find parts.

CNC machines, computers, control boards, power supplies may be swapped in and out.

However I am looking for some way to shut my machine off in case one of the motors had stalled. I have some current sensing transformers lying around.

So I need some kind of Schmitt trigger or a Comparator to toggle down an emergency switch and turn off the program. Am I correct?

Also is there any file that Mach3 writes all the settings to? I would really like to back up my work of setting up this control board. Thank you.

[109jb]

You are running steppers, so the current going to them is already limited. An overcurrent trigger won't work because the current will never go over what you have the driver dip switches set for.

[podolskiy]

You are running steppers, so the current going to them is already limited. An overcurrent trigger won't work because the current will never go over what you have the driver dip switches set for.

I hope that the current is limited and there will be no over-current problems.

Also I am running into this problem:

There are two limit switches and one home switch on each axis in Mach3.
As I understand, the home switch is supposed to be somewhere in the middle to tell the coordinate that it passes a certain place where it is engaged.

Is there any way I can make one of my limit switches into a home switch in such way that the machine will stop and know that it reached a minimum, but so it wouldn't trigger an emergency stop.

My board has 4 limit switch inputs.

I can always wire all my switches in series to make them trigger an emergency stop.

I want a reference switch on one end and possibly another reference switch on the other end. Is there any way to achieve that?

I hope you understand what I am talking about.
Is this called "Soft Limit" or is "Soft Limit" something that happens entirely inside the control software and relies on the distance traveled from "home" position?

I am using Mach3.

So far I have a spindle spinning, motors jogging and emergency switch working.

[podolskiy]

Almost all done setting up.

[109jb]

Home/limit switches can be done multiple ways. The first thing to understand is the notion of "soft limits" which is short for soft-ware limits. The software controller, in this case Mach3, knows at all times where the machine SHOULD be. When you enter that machine parameters into Mach3, you tell it things like maximum positive x-axis travel from the home position, maximum negative x-axis travel from the home position, etc. From this information, Mach3 determines if a g-code move, a jog, an MDI move, etc., will exceed what the programmed limits are. If the move will exceed those limits, it will stop the machine bofore reaching that point. This is how the software limit works.

To use software limits you need a way to set the home position the same every time you turn on the machine. This can be accomplished by jogging to that position and setting home that way. This method would require no switches whatsoever. Or you can do it by using home switches where the machine moves in one direction until it trips the switch and automatically sets that position as "home" for that axis. The home position can be anywhere, and need not be at the same location as the home. For example, if you want the machine home position to be 3 inches in the positive direction from where the home switch trips, you can do that and set it up in Mach 3 that way. That is how the home switch deal works

The "limit" switches are just that. They are set to trip when a movement gets too close to the physical limit of an axis to prevent machine damage. In some cases these switches are wired such that they actually shut off the electrical power to the entire machine like an e-stop would. On hobby machines they are many times wired such that it causes Mach3 to just stop motion an disable the motors. These switches can be wired in series if the switches are normally closed, or in parallel if they are normally open and then wired to a single input on your breakout board.

Now to confuse things, a switch can be used as a combination limit/home switch. For example, the negative x-axis limit switch can be set up in mach3 to act as a limit switch at all times except when the homing process is activated. What happens is during the homing process the switch function as a limit switch is deactivated in the software until the the homing process is completed.

[podolskiy]

Thank you for explaining.

Everything jogs and "homes" all right.
Now I am trying to set up a tool and a "Z" axis.

How do I enter a tool length?
I remember that there has to be a procedure where I would let the tool touch the empty table.

What are "Program Limits" in absolute coordinates? Are those in MM?
I ran a program that makes a circle. Everything runs.

However I had to jog my machine away from the limit switches manually. Is there any way to self-center the Gcode drawing?
I am working only with positive coordinates because my machine zeros at home switches that are also low limit switches.*

*home/limit switches are poorly constructed so they have a problem that as the machine is moving away from "Home" , limits get tripped. Switches need to be debounced along with many other small things that need to get fixed on this machine.