This board presumably does it. But I'm not sure where it is getting the optocoupler voltage from. From the 12v supply? 12V 2-Channel Relay Board Module Active Low | Switch Electronics
That stood out to me too, it makes no sense. The only thing I can think of is it's a badly worded way of saying "if you're trying to drive a lot of devices from your Arduino, you can break out the power for the relay and save current capacity"- basically what you're doing. Otherwise, not a clue. I'd double-check with them on that one. The picture shows the Songle SRD-05VDC-SL-C, which is the 5V version of the relay. There are 3, 5, 6, 9, 12, 24, and 48V versions available, according to the datasheet: http://www.circuitbasics.com/wp-content/uploads/2015/11/SRD-05VDC-SL-C-Datasheet.pdf The optocoupler should switch with 3.3V, in all likelihood; usually logic silicon has an asymmetric switching with hysteresis, like 0-1V for low, 2.5V-5V for high. If you're up for a bit of surgery, you could buy a cheap 5V board, buy a known SRD-12VDC-SL-C relay (and 3.3V optocoupler?) and swap them out, taking advantage of the pre-designed circuit.
I've started buying the parts. There are loads of "TB6600" out there, I'm not sure how much they vary in quality. The ones that look like the link you sent are probably not actually TB6600 but may still be fine. There are others on an open board like this: https://www.amazon.co.uk/Single-Axi.../B01DF3JIDS/ref=sr_1_8?ie=UTF8&qid=1547725856 that maybe are more likely to be a true TB6600 , not sure if it matters for a printer. The closed box type is better for keeping dust out. They are even cheaper on ebay, espcially if you order direct from hong kong - no way to tell if there are quality differences between the ones that all look the same...
I'm also wondering about changing to 24v or more... I'd have to change: * nozzle heater element * part fan * hotend fan * electronics cooling fan (may not be needed with new setup) * what about arduino and relay power? I already have a 24-12v buck converter so I guess I could use that and keep the fans and even the nozzle at 12v and just run the motors at 24v. 12v fans are much more readily available than 24v and I already have loads of 12v parts, so I'd be inclined to only use 24v where it has a clear benefit. what are the benefits of running at 24v or above? more power from the motors I presume - but is that needed? If heat and motor size are the limitations anyway does increasing the voltage improve anything?
TB6600 or TB67S109 "TB6600" makes no difference on anything with negligible current requirements. If it was a router you might need to be more cautious to get the higher current capacity of the true TB6600. These are what I first picked up: https://www.amazon.co.uk/TB6600-Stepper-Driver-Controller-Segments/dp/B07D6L9FM1 - same ones as on Amazon US, get the same good reviews, too. I love them, they've been great. I then added a second Y axis unit for the dual Y steppers from the single ones with good reviews, this one looks to be very similar from people's descriptions: https://www.amazon.co.uk/TopDirect-Upgraded-TB6600-Controller-Segments-Black/dp/B0711J1K66 I went to 24V and got significantly higher rapids and (this could be entirely perceptual on my part) what seemed like more defined, less mushy motions. Zip-zip, stops right on cue. Feels more solid. If you're going to try pushing the print speeds higher, it would probably be worth having 24V, and it'll definitely make positioning and homing nice and quick. I have a 12V PSU going in the enclosure for the laser and fans, but that's it. 24 to the motors, and Arduino powered over USB. Only thing that's powering externally is the active limit switches, which take almost nothing, so I'm not bothering putting in a 5V PSU. 24V heaters would be nice, since they'd run at half the current, but it's probably not a massive deal. I wouldn't worry too much about changing everything out unless you feel like it's actually going to improve the performance, maybe get some other opinions from printing-specific forums and Facebook pages. I honestly doubt very much except the motors would really see a difference though. If you're doing lots of relays, maybe add a 5V PSU, but if it's just one or two, they should be fine being powered from the Arduino- I'd double check the numbers on that though, just to be safe. Arduino's max current capacity on DC power and USB power are noted in the documentation.
what 24v PSU did you use? I have 12v (printer) and 36v (workbee CNC) cheap ones that seems to work fine, but would prefer something with a better reputation ie meanwell or similar.
The Meanwell NES-350-24. About $50. I decided against the LRS-350-24, which is the newer, cheaper (~$33) version of the same thing- but plenty of reviews also suggest it's less reliable. Either one is 350W, or about 15A. Switchable voltage input, too, make sure to check that. Mine came set to 230V instead of 115V. It would be much more catastrophic if the reverse happened to you.
Weirdly I can't find an actual UK supplier for that. It is obtainable from a chinese amazon seller but that's the only source I've found. I wonder if I actually need 15A. Seems to me 10A would probably be fine. ooznest in the UK do a 10A fanless supply which appeals. 12/24V 250W Power Supply - Fanless - Ooznest | Kits, Parts & Supplies
Oh yeah, I never see more than 1.5A in operation between all four motors. I just looked for the best, and that was it, according to a lot of people. If you can find a reliable solution at a better price, whatever works!
