Thread Rating:
  • 1 Vote(s) - 4 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Problems with the limit switch
#1
Hi,

it's me again Angel

I have a problem with the limit switch. It seems like they are always triggered. That meens if I turn on the miniE and want to jog the motor the motor just does a short move, just like the limit switch was triggered. If I plug off the switches from the miniE everything works without a problem. Between the miniE and the limit switches there is a cable with a length of 2,5m. I have doublechecked the cable with a multimeter that everything is connected correctly. But If I connect the limit switch with a short cable to the miniE it works like it should. So I can exclude that the switch is dead. Could it be that the length of the cable is the problem? Huh

Regards Chris
Reply
#2
(08-03-2014, 02:23 AM)Wire14 Wrote: Could it be that the length of the cable is the problem?

I have never experienced this kind of problem with the limit switches. From what you write it might be that the long cables work as an antenna and somehow trigger the limit switch. Do you have any possibility to try a shielded cable to check if this solves the issue?

You'd need to connect the Ground to the cable's shield and the signal to the inner wire. You can test it for example with a regular coaxial cable.

/Airic
Reply
#3
Ok I thought that it could be something like that. Or could it also be a problem that I used just one cable with 7 wires to connect the stepper motor and the limit switch with the miniE? So that maybe the signal through the wire to the stepper motor triggers the limit switch?

I'm going to test it with a coaxial cable and if this works I try a shielded seven wire cable.
Reply
#4
(08-04-2014, 01:24 PM)Wire14 Wrote: Ok I thought that it could be something like that. Or could it also be a problem that I used just one cable with 7 wires to connect the stepper motor and the limit switch with the miniE? So that maybe the signal through the wire to the stepper motor triggers the limit switch?

I'm going to test it with a coaxial cable and if this works I try a shielded seven wire cable.

Yes, that could actually be the problem. Did you use a networking cable? These are already shielded but if motor signals and limit switches are within the same shield they can easily cross-talk.

Cheers.
Reply
#5
Ah ok, no I used a normal unshielded cable. So do you think a normal shielded cable should be enough or should I use a networking cable?

Greetz
Reply
#6
(08-04-2014, 01:42 PM)Wire14 Wrote: Ah ok, no I used a normal unshielded cable. So do you think a normal shielded cable should be enough or should I use a networking cable?

Greetz

No - just use the cheapest shielded cable you can find. There is no need to use a networking cable. Any shielded 1, 2 or 4 core cable (one core for each limit switch). Connect the limit switch pins to the cable-cores and Ground (GND) to the shield (see attachment).

On the switch side, connect each switch to one core-cable and to the shield (which is ground).

Let us know if it worked.


Attached Files Thumbnail(s)
   
Reply
#7
Ok I try it. And you think it is not a good idea to put the motor wires and the limit switch wires together in 1 cable? Because I want to avoid to many cables between the slider and the miniE. (Motor, Camera, Limit Switch)
Reply
#8
Ok I think the ground cable was the problem, I let the 4 wires together with the two wires of limit switch 1 and 2 and used a seperate wire for the ground and I think that it works now. Because if I jog the motor I see the cm going up till I hit the limit switch. But my new problem is that I have maybe damaged the Big Easy Driver. Yesterday evening I turned the miniE a cuple of times on and off because I tested the sd card. And now the light of the Driver isn't lighting anymore, and the motor doesn't move. Can I test if the driver is damaged or just a connection is broken?

Ohhh this is going to be a never ending story... Sad
Reply
#9
(08-04-2014, 11:24 PM)Wire14 Wrote: Yesterday evening I turned the miniE a cuple of times on and off because I tested the sd card. And now the light of the Driver isn't lighting anymore, and the motor doesn't move. Can I test if the driver is damaged or just a connection is broken?

Just turning the system off an on again will not cause any damage. It could damage a stepper-driver if you have the motor powered and unplug it while it is powered. A stepper driver could also be damaged if you turn the motor too fast so that it works as a dynamo (e.g. falling slider on the track).

If both these things did not happen it is more likely to be a loose connection.

Good luck!
Reply
#10
(08-05-2014, 10:04 AM)Airic Lenz Wrote: [quote='Wire14' pid='7505' dateline='1407183880']

Just turning the system off an on again will not cause any damage. It could damage a stepper-driver if you have the motor powered and unplug it while it is powered. A stepper driver could also be damaged if you turn the motor too fast so that it works as a dynamo (e.g. falling slider on the track).

If both these things did not happen it is more likely to be a loose connection.

Good luck!

I haven't done both mentioned things. So I hope it is a loose connection. Is there an option how to check if a connection is loose? I checked the cables between the shield and the driver board, they are ok.
Reply


Forum Jump:


Users browsing this thread: 1 Guest(s)