Hello Guest it is May 21, 2019, 07:14:32 PM

Author Topic: limit switch trouble  (Read 7400 times)

0 Members and 1 Guest are viewing this topic.

Re: limit switch trouble
« Reply #20 on: March 04, 2008, 06:10:07 PM »
Well.......if it ever comes to mind.......FOR GOD'S SAKE WRITE IT DOWN !  :D
Glad you got it going.
RC   8)

Offline kak

*
  •  73 73
    • View Profile
Re: limit switch trouble
« Reply #21 on: March 05, 2008, 12:45:36 PM »
Hi, Adam

Your use of pin 11 for all axises in incorrect, Should be Ground.

Pin 10, X--, X++, X home in series other end to Ground.

Pin 12, Y--, Y++, Y home in series other end to Ground.

Pin 13, Z--, Z++, Z home in series other end to Ground.

Hope this Helps, Chip


Chip - do you really mean my connections are wrong?  Its working fine.

All my Limit switches are on the end of each axis, in series and go to pin 11 and ground.

Maybe it works both ways, yours is just easyer and uses 3 pins - I use 4 pins.

Adam

Offline jimpinder

*
  •  1,233 1,233
  • Wakefield, West Yorks, UK
    • View Profile
Re: limit switch trouble
« Reply #22 on: March 05, 2008, 01:17:25 PM »
To put a stop to the argument -

All limit and home swtiches do, is send a signal to the computer. It makes absolutely no difference if they send a 5 volt signal or a 0v signal. The system will stiill work. Mach 3 can be configured in either way.

Neither does it make any difference if you wire all switches seperately, or in series to save pins, Mach 3 can accomodate them all.

However you do it, all you want is your table to stop when it hits a limit, or home to the same place every time when you hit home.

The only reason for saying  switches should be normally connected to 0v - and then pushed open to send the signal - i.e. using the internal pull up resistor to raise the line voltage to 5 volts is for safety. Should any of the wires break, or come loose, or the switches fail, then the system will signal a limit switch open, and stop, before any other damage is caused. I don't think, in my case it would cause much bother at the speeds I travel, but some of these big fast rigs could cause a bit of damage if they didn't stop when they were supposed to.

I looked through this earlier, and couldn't understand the diagram - have you seperate switches for limit and home - it would appear so from your description. This is not necessary since one switch can double up as a limit and a home switch - the computer knows what to do, and it saves you inputs - but if it is working, don't touch it - the main thing is it is working.

You should not, now, need to touch your limits again. You can set your soft limits just inboard of your physical switches, and your table shouldn't go anywhere near them.

I must admit I found my home switches (allied with the limit switches) in a most inconvenient place, so I am now working on a laser homing device to put my table somewhere useful.



Not me driving the engine - I'm better looking.

Offline Chip

*
  • *
  •  2,057 2,057
  • Gainesville Florida USA
    • View Profile
Re: limit switch trouble
« Reply #23 on: March 05, 2008, 01:43:38 PM »
Hi, Adam

Your  " i do not know what fixed it. i have been fooling with the switches for 2 days."

There are many ways to setup Limit switches, With or without a B-o-Board.

Each Axis, It's own Pin.

Pin 10, X--, X++, X home in series other end to Ground or 5volt's, Depending on your Active Low setting in Inputs.

Pin 12, Y--, Y++, Y home in series other end to Ground or 5volt's, Depending on your Active Low setting in Inputs.

Pin 13, Z--, Z++, Z home in series other end to Ground or 5volt's, Depending on your Active Low setting in Inputs.

All in series and use one pin.

Pin 10, X--, X++, X home, Y--, Y++, Y home, Z--, Z++, Z home, All in series other end to Ground or 5volt's, Depending on your Active Low setting in Inputs.

If pin 11 is an Input, Then it sounds like you wasting it, You gust need the Gnd.

Thanks, Chip