I need super basic Help with Hardware choices

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5 years 4 months ago - 5 years 4 months ago #211631 by Twizzlermill

Aaroncnc wrote: Do you have an old pc with the right ports to work with the break out board?


I got some old laptops lying around, some from 2006-ish.

Yeah, I already read somewhere else that USB options seem to exist, but are considered a bad choice.

I think for now, I'll just get some hardware and have a go at it, but I have one last relatively unrelated question:

The motors I want to use are rated at up to 50V, but according to JMC, are typically used with 36V. I already read somewhere else that running them at their rated maximum (so 50V) would be a bad idea (If I understood correctly, this has to do with the motors turning into dynamos when the machine brakes – or was that with servos?Plus a chance of overheating, I guess.), but how do I decide what's the right voltage for me? Should I go as high as possible, but with some "reserve"? If yes, how big should that reserve be?
Last edit: 5 years 4 months ago by Twizzlermill. Reason: Clarification

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5 years 4 months ago - 5 years 4 months ago #211634 by Aaroncnc
as far as the voltage i would contact the manufacturer with info of your system.
yes when the machine slows down its possible for the motor to feed back voltage.

This is also why in alot of system i have seen they dont use switching power supplies but big transformer based ones for the drive motors.

more voltage will allow you to go faster to a point but heat dissipation from the motor can become a problem and may need an active cooling solution.

I would stick around or just under 40V DC.

you might leave a bit of speed on the table but i doubt it will be that much the extra few volts will get you vs the problems that may come in the long term of running up against the rated max.
Its no fun in the middle of a 7 hour part a drive motor overheats and kicks off but the machine keeps going.
Last edit: 5 years 4 months ago by Aaroncnc.
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5 years 4 months ago #211636 by tommylight
Just to be on the safe side, are you sure those are steppers as i have not seen those made bu JMC, but i never looked closely.
If those are the Nema23 ones with the drive attached to one side on the motor, those are servos that use step/dir control, not steppers.
Usually servos are better, but that highly depends on what they are used for.
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5 years 4 months ago - 5 years 4 months ago #211637 by Twizzlermill

tommylight wrote: Just to be on the safe side, are you sure those are steppers as i have not seen those made bu JMC, but i never looked closely.
If those are the Nema23 ones with the drive attached to one side on the motor, those are servos that use step/dir control, not steppers.
Usually servos are better, but that highly depends on what they are used for.


JMC makes both servos(e.g. iHSV57) and closed loop steppers(e.g. IHSS60), which look pretty much the same.

I decided not to fuss with servos, because they seem to need more active calibration and from what I gathered, the size of my router (more specifically the length of the spindles) limits travel speed anyway.

I would stick around or just under 40V DC.

you might leave a bit of speed on the table but i doubt it will be that much the extra few volts will get you vs the problems that may come in the long term of running up against the rated max.
Its no fun in the middle of a 7 hour part a drive motor overheats and kicks off but the machine keeps going.


Thanks, thinking about it a little more, that's what I assumed as well. In the end, 90% of what I'll be working on will be MDF, so I can live with a little less power.
Last edit: 5 years 4 months ago by Twizzlermill.
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5 years 4 months ago #212272 by Twizzlermill
I got another question, which may be considered off-topic: I stumbled upon the Protoneer CNC Raspberry Pi Hat. It seems like I can link up external drivers with relative ease. I'm assuming linking up a JMC CL stepper will be possible.

Do you guys think this is a viable alternative? I tried looking for its limitations, but I didn't find much, apart from a "limitation" of 1/32 microsteps (which still sounds like way more than I'd need…? And I'm not sure whether this only applies to the small drivers, instead of external drivers). Speed maybe?

Kind regards,
Twizzler

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5 years 4 months ago - 5 years 4 months ago #212338 by andypugh
Is the interface step/dir on GPIO pins, or does it have some higher-level interface to on-hat logic?
Last edit: 5 years 4 months ago by andypugh.

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