RAMS or Megatronics for stepper control (not for 3d printer)?

Hello, I need a stepper controller for arduino mega, to control 3 nema 17 steppers. Can I use RAMPS 1.4 or Megatronics for this?
Megatronics has the arduino mega built in as I understand.

The tricky part is I need some code samples to make this run as this is not for 3d Printer but rather some automation tasks.
So I need to know do I need separate stepper drivers for arduino mega or can use the boards above? Where to get code samples?

yes that hardware will work to drive your steppers, here is your but though. what are you doing.? you may wish to look into something called a CNC Shield, it may be more suited to your taks. http://blog.protoneer.co.nz/arduino-cnc-shield/

all gcode is, is the instructions for the controler on where to move next, X,Y,Z, E

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[mike-mack.blogspot.com]

RAMPS is mainly just an interface boards for stepper controllers, with Megatronics being that same board with an Arduino Mega on board. They also provide a few inputs (thermistors and end-stop), and a few outputs (FETs to control stuff), and in some cases generic I/O (servo pins, expansion headers, etc). You still need a number of Pololu A4988/DRV8825 (or compatible) stepper driver boards. Both have sockets on them for these boards (depending where you buy, they may be included or not).

The advantage of these boards is simply that it does all the hard connection work for you. You can easily drive them with your own code. You just need to set the right pins and toggle them appropriately. I know somene who is using 3 steppers on a RAMPS board with some simple code to control a loom.

Most of the firmwares are complicated so reading them as an example is not going to help you with getting to know how it all hangs together. There is some test firmware somewhere that simply drives the motors in certain predictable patterns. I can't remember the link and couldn't find it just now, so someone else might help on that front.

Basically you need to set the enable pin appropriately (depending on the board, it may not have one, or it might be common between a few pins, or each stepper may have it's own - always check), then you set the direction pin (direction always depends on the motor wiring which can be inconsistent, so experiment) then you pulse the step pin the number of steps you want it to move. Note that the "steps" are actually depend on the microstepping jumpers - so 1 step pulse will get you 1/16th of a step if the jumpers are set for 1/16th step. You just send a train of multiple pulses to get the number of steps you want.

Notes:
There is no feedback loop, so you don't know if your step succeeded. You could put an encoder on it, but none of the 3D printer electronics really do that - they rely on you tuning the stepper drive appropriately.
The "pulse" needs a reasonable duration. I don't know what the minimum is (check the spec sheets for the Pololu A4988 or DRV8825 boards), but things like 1-2 microseconds is usually way too small.

I'm just need a controller for DIY telecine project.

I need 4 nema 17 steppers to turn in unison, I found this made in china CNC controller, but the sounds (vibration) of the motors at low RPMS is unacceptable
[www.youtube.com]

I watched many RAMPS board videos and motors turn very quiet and does not vibrate. But despite the hard config for other things then 3d printer I think I will not use it then, There are many driver version for RAMPS is the DRV8825 latest and best? What about A4988 what would you use ?

I wanted to connect all 4 motors to same controller for easy controlling given the fact they need to do everything the same, but can't find reliable controllers that does not cost hundreds of $.

I found this [www.ebay.com]
This looks promising at least from description:

"The TMC260 is the first energy efficient high current high precision microstepping driver IC for bipolar stepper motors. The unique high resolution sensorless load detection stallGuard2™ is used to for the world’s first integrated load dependent current control feature called coolStep™."



So I don't know what to use the CNC shield with A4988 or DRV8825 or Arduino-TOS-100

It uses the same drivers has the ramps board. You might even just want to look at some of the arduino examples if all you want to do is turn them all the same. A proto board and a little soldering might be your best option. The drivers are fairly simple. Look at sparkfun.com at there easy driver. If I remember right.

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[mike-mack.blogspot.com]

Since they're all moving at the same time, you could simply drive the inputs in parallel (ie: hook up a bunch of driver boards with their minimum components, connect step/dir/enable in parallel to some Arduino pins, then just do your movements).

There is nothing special about the wiring on a RAMPS or Megatronics board with regards to using the A4988's or DRV8825's.

The reason most of the RepRap printers are fairly quiet is that they're using microstepping when driving the motors. The A4988's have a max microstepping of 1/16th, while the DRV8825's have a max microstepping of 1/32nd. The DRV8825's also handle a little higher current motors, so it's what many people are using now, and what I'm planning to use on my next machine. Also, most stepper drivers are least accurate at their max microstepping setting, so you can run a DRV8825 at 1/16th step and get more accurate microsteps than out of an A4988. I don't believe this is MUCH of an issue, but if you're really worried about precision, definitely keep it in mind.

Here's the product page for the Pololu DRV8825, which has PDF datasheet that covers how to hook it up and use it. [www.pololu.com]

PS: There is a simple way to set the motor current using a voltmeter (measuring the Vref pin on the DRV8825 board). You need to know your motor current specs and make a simple calc to figure out what it is, then just adjust the trimpot so that Vref is the value you calculated. Details should all be in the spec sheet. If you have issues, feel free to ask.

Edited 1 time(s). Last edit at 01/08/2014 04:27PM by Cefiar.

What about using a driver such as DQ420MA , Motors 42BYGHW208 1.8, 12V, 0.4A, 4wire.
[www.youtube.com]

motor
[www.wantmotor.com]

driver
[www.wantmotor.com]

Seems driver is able to support up to 256microsteps.

Can I connect 4 motors to single driver? Or do I need 4 drivers for 4 motors?

These are basically the same thing as the A4988 or DRV8825's to drive, but yes they support more microsteps. Note that if you're after high speed, mirostepping is your enemy, as you'll only get a finite number of pulses out of your electronics to feed these devices, which sets a finite maximum speed you can spin the motors. You can of course change your stepping (via switches) so in that way at least you can experiment and see how you go.

You could hook the motors up in parallel (it's how most RepRaps work on their Z axis) and it should work fine. If you're using a large enough supply, you could hook them up in a parallel/series combo as well, but that's getting a bit complicated (eg 2 motors in series, then the 2 series pairs in parallel).

Note that at a guess, if you go with an all-parallel motor setup you'll have to set the current limit to about 1.6A (4 motors x 0.4A), but don't take that as granted, as I'm not sure if that would be the Peak value or the RMS value.

As with anything like this though, I would suggest you check the motors you get for shorts on any of the coils BEFORE hooking them up. I'd also try one motor first, then 2, 3, 4 (in order) to see if there are any issues. You may find that you can only run 2 off each driver, in which case you would need 2 drivers. I've seen lots of drivers destroyed by motors that come from places with poor quality control or that are damaged in shipping (dropping a motor on its shaft can damage the electrical contacts inside, leading to a short).

Thank you for all the info. I think I'll go with the TMC260 chip TOS-100 controller, I contacted the shop say they are very good, diagnostic software is cool too.
They support up to 256microsteps (the once from china does not). I can easily diagnose any problems with the diagnostic software.

I decided to get a controller for every motor. Arduino mega to drive them because I read that connecting Step, DIR pins is not recommended. So I need a bunch of pins to drive them, plus sensors, LCD etc.

I'm looking for smooth low speed, very little vibration. TOS-100 controller can drive up to 1.7A can anyone recommend quality motors?
I've seen [www.ebay.de]

I need 6 steppers. So very expensive ones are not an option.

I didn't notice that the sound of the motors in your first video was particularly bad. Is noise or vibration a particular problem? Steppers tend to be like that.

It's difficult to recommend motors, because we don't really have any detail about your application. If you want to drive the motors in unison, then I think it would be better with a single controller and using Step/dir. A Mega has plenty of pins anyway, it might be easier to sync those than SPI.

But I guess if you are spending $100's on controllers and drivers (probably unnecessary), you don't want to skimp on the motors. The motors may be the most critical part.

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But I guess if you are spending $100's on controllers and drivers (probably unnecessary), you don't want to skimp on the motors. The motors may be the most critical part.

I don't want to buy the parts two times, and I don't want any vibration that could be avoided. The TOS-100 has 256 microsteps at slow speed I think it will be way better then the A4988 or DRV8825. Since it's not made in china and doesn't seem to have failing parts like made in china caps, I think it will be at least easy to use.

Yes motors are critical part, I'm trying to find a decent motors at good price, I'm trying to find 0.9degree NEMA 17 motors up to 1.5Amps to be safe.

if your motors are just turning, why not look into a geared dc motor, or is there a reason you need a stepper.?

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[mike-mack.blogspot.com]