Let me untangle my Spaghetti – Clem’s Numerical control

RE: Let me untangle my Spaghetti – Clem’s Numerical control

DAB — Thu, 16 Feb 2023 19:57:33 GMT

Hi Clem, have you looked for any cross talk on the wires?

The high current spikes on the stepper motors could introduce problems on signal lines.

RE: Let me untangle my Spaghetti – Clem’s Numerical control

shabaz — Wed, 15 Feb 2023 19:46:14 GMT

Hi Clem,

Regarding: "Matching ferules to the right cable size is not always trivial as they seem to be mostly made for AWG sizes and not metric cable sizes"

It's a topic there is little literature on! : ) I too came across this issue a while back, and wrote this guideline, I don't know if it will help, but it's a starting point, it specifies between what range of AWG values will fit inside ferrules that are then crimped into a square cross-section. So, for instance, if your wire is (say) 1.2mm2, then that is 17 AWG using online calculators, which means the red ferrule is (the table is just a guideline however!) best for that (the color coding is different for France and German standards, but it is easy to see which is being ordered usually). The H value in the table indicates the minimum diameter hole needed for the crimped ferrule to fit in, so you can measure your screw terminals with calipers to see if it will fit or not. (The assumption is that the crimper is making a square shape).

RE: Let me untangle my Spaghetti – Clem’s Numerical control

shabaz — Wed, 15 Feb 2023 17:45:15 GMT

I too thought about this a while back (I have a small CNC table that needs a controller), and have unfortunately made zero progress for years. At the time, I was considering using ready-made cables, to save having to do as much crimping.

The plan was to create PCB adapter boards (shown with red arrow) that would plug or screw onto the drivers (e.g. using terminal blocks, or terminal pins), and adapt out to a connector (e.g. perhaps short RJ45 cables [shown with grey arrow], since they come in a range of convenient lengths). For the power connections, I would do a similar thing (shown with yellow arrow), and either parallel up many pins of a RJ45 connector (I did check the PoE standards to see how much current is possible per pin, but I've forgotten what I concluded at the time), or crimp those, e.g. Molex Mini-Fit Jr or similar, again paralleled connections if higher current needed. Having two connectors for the power would mean I could reserve the possibility of daisy-chaining power like a bus, or just plug into one connector for star-type distribution, i.e. I'd worry about that problem when it came to plugging it all together, and see what worked out best.

RE: Let me untangle my Spaghetti – Clem’s Numerical control

dougw — Wed, 15 Feb 2023 16:03:59 GMT

This what I call a brave project - it takes intestinal fortitude to tackle something of this magnitude. Even the space requirements to work on it would be a logistical nightmare for me. Kudos for persevering...

RE: Let me untangle my Spaghetti – Clem’s Numerical control

dougw — Wed, 15 Feb 2023 15:58:14 GMT

Is it possible to use a larger bootlace terminal that will accommodate all the strands and then flatten it a bit in a vise so it fits in the screw terminal?

RE: Let me untangle my Spaghetti – Clem’s Numerical control

beacon_dave — Wed, 15 Feb 2023 15:01:36 GMT

"...I had to thin down the strands a bit to get them into the largest ferules possible that still would fit the screw terminal on the boards..."

You could try this style of terminal crimp instead of bootlace ferrules: