My Cheapo Chineese 3020t mini CNC Build (more like improvements) leanring all the way

[Zeeflyboy]

your limit switch plugs are 4 pin... I assume that is to allow two switches per axis? sorry to state the obvious but have you definitely wired up to the correct pins in the plug for the Y-axis if that's the only one not working? You could have got the two switches crossed over such that the circuit is never closed and thus you would see no change on the IO.

[ravihotwok]

yes mate pretty sure, the x and y axis have 2 switches wired in series (but I had the wires the wrong way around so I know they wont work. But on the z axis I only had 1 switch at the top of the z axis. When you press the switch the input on the software screen lights up. If you un plug it and place it in the x axis the input for the x axis lights up on the screen so I know the plug is working on the box. When I try it in the y axis nothing happens on the software screen which is making me think something is a miss with the box if that makes any sense mate

[Zeeflyboy]

ah I get you...

I would double check your soldering on the Y-axis input then and also double check however that inputs/outputs board connects to the motion controller is plugged in fully and all required wires are present and correct.

If you have a multimeter you can check for any shorts on the input side, continuity between any of the pins would show that you have a short in there which would present a permanently closed circuit, thus any opening of the circuit by the switch wouldn't have an effect, giving the result you are getting there. Worth a check. You can also check that you have continuity between the board and the motion controller on that line.

As an aside, while nice to have, limit switches certainly aren't a necessity on a machine this small with weak motors like that - it won't have the power to damage itself and you can just start it up in one corner and set soft limits if you like. My first machine never had any limit switches at all, my second machine only had one set for "home" and soft limits for the end stops. Nothing to stop you from using it "as is" while you figure out your limit switch issues.

[ravihotwok]

Cheers mate, I was aware of this, but I am also more aware of my lack of experience with these machines so wanted some safety precautions lol I still have a cork on a fork when I eat to prevent accidents lol

[Zeeflyboy]

Yeah but my point is you are eating with a rubber fork anyway with this machine - it's not going to be powerful or fast enough to cause itself any damage from hitting the stops. The safety is built in by it's lack of guts

Just something to consider if the y-axis proves more difficult to track down than some chasing with a multimeter.

[ravihotwok]

yeah totally understand, we have tested it with a multimeter and all seems to be ok I think (but it was my mate who tested it)

I spent a lot on this box so if there is a fault with this box or a internal board I would like to get to the bottom of it, but it is nice to know that it wont self destruct the machine if I do make a mistake when operating it,,,,,,,,,,,,which is inevitable :-)

[Zeeflyboy]

While it's certainly always possible theres a fault in the hardware, I find 9 times out of 10 it's operator error and I've just done something silly or overlooked something. Do some investigating with a multimeter and you may well find it's shorted or not making it all the way to the motion board input.


I've found a schematic for your driver board - my assumption was correct... you will want to set the jumper to the second from last set of pins to allow it to use 2.0 Amps (has 2A next to the pins). That would explain your motors being so pathetic as they were only getting half an amp. You can also see the dip switch settings to set microstepping which will give you smoother motion. You will need to then adjust steps per unit to match however.

[ravihotwok]

awesome detective work there, I was too busy trying to find a schematic for the whole box. didnt think to look for a schematic for the individual driver (actually forgot they existed)

[ravihotwok]

here is a pic of the soldering I did, the limit switch plugs are on the bottom.

I cant see anything obviously wrong from the picture, to check the back of it would mean removing all the soldering to allow it to separate. Am I correct in understanding that I could program the end socket to act as the y axis input if it works?

Just an idea

[Zeeflyboy]

Really the easiest way to check for shorts or a break in continuity between points is using a multimeter... anything else is just guessing. If you don't have one, they are fairly cheap and extremely useful when doing anything remotely involving electronics.

Yes it is probably possible in your software to assign whatever switch input to whatever axis, but I have no experience with the planet-cnc stuff I'm afraid.