Limit switch rated voltage?

[mealman]

I am on a project of building a 3-axis CNC milling machine. I have purchased the breakout board from CNC 4 PC, stepper motors and gecko drives G203V. I am using MACH 3 as the software, so I'm using the parallel port to send out commands (PWM of 5V).

When I read the data sheet for limit switches I found from RS Australia, the rated voltage is usually 8, 14, 30 and upto 250 VDC. Where do I get these voltage supplies? Initially I thought the limit switches will be powered by the 5V on the parallel port. How should the limit switches get power from, the parallel port, or some other power supplies?

Lastly, do you guys have any good supplies of limit switches? I am looking for $10 to $30 and I might need 6 of them.

Thanks in advance!

[Greolt]

The switch voltage rating is just a maximum.

Most home builders will run their limits on 5v with the BOB providing either optoisolation or buffering.

There are other ways to do it. I personally run mine on twelve volts (I already had that handy in the control box running fans)
This can help with noise issues on normaly closed limits. Most industrial applications run them on 24v.

But I would not worry about that at your stage of building.

In fact most of the blokes I know here in Aus with homebuilt routers are quite happy with no limit switches at all.


Have a look at this ebay seller. They have a range of limit switches.

http://stores.ebay.com.au/Claraworld...QQftidZ2QQtZkm

Greg

[epineh]

Originally Posted by Greolt In fact most of the blokes I know here in Aus with homebuilt routers are quite happy with no limit switches at all.

Hey, I have limit switches...erm... in a drawer somewhere

I did install one on the X axis... one day I may even connect it to something Besides servo's are much more fun to play with !

Russell.