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alberto

3-Axis Stepper Controller

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Thanks MP, you brought something to my attention though. The schematic shows C1 = 0.01uF, C2 = 10uF Polarized, and C3 = 0.01uF but the board parts lay-out shows C1 as being polarized. I hope this is NOT a problem, I laid my board out just like the parts lay-out shows, it seems to work. I hooked it up to a 555 signal generator and the stepper motor steps. Also this is my first attempt at making a hobby CNC what software would you recommend and are their any other pitfalls I need to look for when making the CNC machine? My primary goal is to make PCB

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You should have no problem with the non polarized. I normally use tantalums for this value. I keep quite a stock of them for micros. The larger caps should be polarized ones, though.
There is a cad program out there called DanCad. It might be what you are looking for. I wrote my own but it does not use the standard NC drill format. It uses X.Y coordinates. I had intended to later add a module for the NC drill format, but never had the time to go back to it. If you are familiar with programming you can write your own program. You just send pulses to the parallel port in the form of binary numbers (1s and 0s). The ones are the pulses for the motors.
Here is a tip (a real time saver): Make yourself a small board with LEDs and resistors to connect to the parallel port to test the program before you send anything to your project. You will want to know you are pulsing the right pins before you connect to an actual stepper.

MP

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I think the quill is not rigid enough. When it is all the way down it has a play of 2-3mm!! (at least the small ones like this). Where I work we have bigger (and more expensive) drills which I guess could manage the side forces).

You could replace the bearings (and add some more) to make the quill more rigid.

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Alberto, this would make a cnc if you already have these parts and choose to add the steppers and controller. But if you do not already have these parts, I think you would spend more money for these than just building a unit from the ground up. As greekpic has stated, side play is a very important concern if you intend to make precise duplicates.
Have you decided upon a software package to run this? I am just curious.

MP

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Any detailed picture of xyz board? I mean, complete with terminal blocks and limiting switch, etc ... I know everything is in the schematics, but I think it would be good to see the "as-built".

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Mp i think that it's the best choice, because with less dimensions it offers greater power as regards a traditional one.
I found that toroidal in a old power supply bought in a surplus shop.
it has a diameter of 100 mm and develops about 22Amp without any buzzing or overheating.
The best thing is that I have paid for it only 12 euro!!! ;D

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MP i have a question for you:
If you measure with a digital volmeter pin 11 and 14 of ucn5804B which value do you have (before and after a motor startup)?
I think that my ttl computer parallel port voltage il too low! Before the motor startup pin 11 is 0.23V and after 0.53 V but anything moves it can be the resistor network?
(On pin 14 i have a value of 6.7V and my software is turbocnc)

post-30-14279141920136_thumb.gif

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Alberto, you should have 5 volts coming from the parallel port. Perhaps you could check these pins with the UCN5804 disconnected. It is also necessary to add a large delay to the program or you will not get a good voltage reading. This is a fast pulse of 5 volts, so it will be hard to measure unless you slow it down. You might get better result with a logic probe. Some parallel ports only give about 3 volts, but I have only seen this on some (very few) laptops.
I made a small board with LEDs on the control pins tied low with a resistor of 470 ohm. When my program would light the LEDs, I knew it would pulse the motors.

MP

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MP i have tested my parallel port without ucn 5804B.
first with leds an after with a digital volmeter and when pin 2-3-4 are hight (stepper pulse) and pins 5-6-7 (stepper dir) there are only 2.6volt!!!
How can i do?
Is a problem of turbocnc? (there are a lots of parameters to specific! as frequenze.... )
My cnc computer is an IBM aptiva pentium1 133Mhz
You think that an Opto-Isolated version is the solution?

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You can use pull up resistors. MP can help with the values, but tying a resistor between each pin and +5V will make shure it's +5V when high. When its low it's grounded so it's 0V regardless of the resistor.

Hope that helps.

Nikolas

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Here you are some pictures of my electronics box with 3-Axis Stepper Controller and relay board! ;D


Beautifull work! :) Can you send a zoomed in picture only for the XYZ board with components and connections?

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Alberto, assuming you have used the slowest delay possible so that your pulse is not faster than the device you used to test it, then I would believe you might have a problem with your parallel card. I cannot see how the program could cause this problem since the program only tells the processor to send pulses. It does not tell the computer what level to send.
You can use opto isolators and pull up resistors, but be sure this output voltage is not due to something going out on your parallel card or you will have other problems later. If you need to use pull-up resistors, the voltage should be +5 and the resistor should limit the current to the spec of the opto isolator you use. For example, if it you want 10 ma of current, 5V/470 ohm = .0106 amps. Close enough. This is a pretty standard value for these devices.

MP


MP

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These two power resistors are used to limit the current to your steppers if this is needed. Figure out how much current your stepper can take and use this resistance to keep the controller below this amount. It is not published because you will have to calculate it from your stepper specs. If you do not need it, it is best to leave it out.

MP

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