Help with limit switches and Xylotex board

[dowling177]

I have gone through most of the threads on Xylotex concerning limit switches but am still confused by the options anyone has if they want to put limit switches on their machine.

I am looking on purchasing the 3-axis drive box (since I am just starting out and learning about CNC controls, and need a controller ASAP for a school project that I am doing).

It looks to me as if you can hook limit switches to the Xylotex board using the J11 and J10 terminals (from the Parallel Home Switch pdf which is on their website).

Is this true? or do you need to buy a breakout board and hook that up to the Xylotex board?

Any input about Xylotex boards and limit switches is appreciated (I don't understand much about electronics or schematics).

Thanks

[ger21]

You'll probably need to either make a board to mount some pullup resistors to for the switches, or buy a breakout board that's set up for switches already. Something like this would probably work OK. http://www.cnc4pc.com/Parallel_Port_Interface_Card.htm

[ger21]

The current Xylotex boards no longer use the J10 and J11 terminals. All unused parallel port pins have screw terminals. But like I said above, you'll still need to add the pullup resistors on a seperate board.

The Xylotex Unipolar board (you assemble) has provisions for the pull-up resistors on the board, which should allow you to hook your switches up directly to the board.

[coherent]

You didn't say if you have a newer or older model board. Either are capable and have the connections to hook up limit switches, and as Gerry said the older 3axis board uses J10 & J11. If you look on the xylotex web site under the data sheets, there are schematics for simple series, or parallel home switch setups. You'll need one or three 10k resistors (depending on which way you want to wire them) and a +5v supply to pull the circuit low. You don't have to have a board, you can just put the resistor(s) inline and use some shrink tubing. You can set up for normally open (NO) or normally closed (NC) switches. If all you have is NO switches they will work but with a NC switches and circuit it will also stop things if a limit switch wire breaks, unlike the NO circuit. You have lots of setup options for limit or home switch setup with software like Mach2, but I don't know what you're using... I'd really suggest a breakout board tho... a simple one for about $75-80 from PMDX will not only isolate your computer's parallel port from damage, but will have the resistors built in to pull your switch circuit low as well as a 10amp 120v ac relay built on the board for spindle control. That paticular board also has a watchdog circuit (also called a charge pump circuit) that will stop things should the software runnning on the PC stop working properly. I know Mach2 has a charge pump feature, but any software that will toggle pin 17 on the PC's parallel port will work. Most steppers are capable of doing some serious damage to your machine if something goes wrong. It seems like a fairly inexpensive safety "bridge".
-marc

[UKRobotics]

What is this PDMX board you are refering to, and where could I obtain one ?

[JoeyInCali]

What a pain in the jazz!
I want to hook mine up too but it has the male parallel hookup in the back.
http://cgi.ebay.com/ws/eBayISAPI.dll...m=330274305901
I bought that too.
Why can't they just make a control box with easy hookup for limit switches and maybe an AC outlet or two for Spindle and coolant?
just venting, sorry