I'm planning a large plasma/router for my fabrication business and would like to use arduino to save some money. I need to use higher voltage steppers (60-80v) to turn my big 4th axis for cutting pipe slots. I'm also looking to add cnc to my mill which would require more than a nema 24. All the shields I see for the Uno only go up to 24V. Is there a way to bypass this and use some bigger drivers with the arduino and shield only providing signal level control?
My proposed solution is to use a 5V power supply through the shield and connect the output of the step stix to the direction control of the larger stepper drivers which then get their power from the higher volt power supply. I'm wondering if this will cause any delay or interference issues...
Nope. You're on the right track. At that size you should be using a motor driver module that accepts TTL inputs. Then you can wire it direct to the Arduino without external level shifters. Just make sure the grounds are tied together or opto couplers are used.
There is a significant risk of this IMO. Be vary carfeul with ground connections, supply filtering and screening. I have found that it is usually easier and lower cost to put in extra at the early stage than trying to retrofit.
For that kind of power you're going to need serious drivers, not the sort that comes on a shield. There are a lot that come in the same form factor as the one @madmark2150 showed you. Some of the high end ones are quite expensive (especially compared to a shield and considering you need four) but should be more reliable. Buy at least one spare too.
Usually, Pololu comes up in discussions like this, but you're going to need to look at Leadshine and the like I suspect.
I am going to second the suggestion by wildbill to look at some good drivers and steppers.
I have had good luck with StepperOnline. They have various grades of motors and drivers available.
They have a good selection of steppers and matching drivers. I would strongly recommend a closed-loop stepper. It is only a little more pricey than open loop, but will keep the motor from missing steps.
I'm looking at putting in a stepper for the Z-axis of my manual small mill and I will likely be using a 5-6 Nm motor from them. It will not be for CNC but mainly because I'm tired of cranking that handle
I will also buy the connecting cables for the motor and the encoder from them. I looked at making my own connectors, but for the price it is not worth the hassle. The encoder cable is shielded, but I don't think the motor cables are. Since you're doing plasma, you may want to look at whether you need shielded motor cables too.
Hope this helps
Thanks a bunch. I’ve been reading a lot…one thing I haven’t been able to tease out is what the shield actually does. Is it just another board with drivers on it or does it actually do any processing? I guess what I’m asking is would it be possible to just wire my stepper drivers directly to an arduous mega or if I need another device like a shield to handle the extra inputs/outputs of a CNC system
You don't need a shield - it's just a convenience to connect everything together. Given the stepper drivers you'll be using, the shield won't be useful.
Motor shield is easy no wiring method to connect to Arduino. Motor end needs wiring no matter what. Motor shield is similar to module I've shown before, just ... less.
