Messages

2601

General Mach Discussion / Re: E-STop & Limits Wiring...

« on: January 25, 2014, 02:11:30 PM »

Just trying to figure a few settings out, my BOB hS a relay on it for spindle control, which options do I need to set in mach setup so it comes on with the torch-on code??

I'm going to use the bob relay to drive a larger relay for a bit more isolation, this will then drive the plasma cutter.

2602

General Mach Discussion / Re: E-STop & Limits Wiring...

« on: January 19, 2014, 04:16:05 AM »

Excellent, I have a lot of small din-rail mount relays I can use.

This would give fairly good noise immunity and also reasonably good voltage isolation as the relays have a fairly high flashover rating from coil to contacts.

I have a steel cabinet to mount the BOB and drivers in, might also strip the PC and mount that inside too, keep it all in its own environment etc.

2603

General Mach Discussion / Re: E-STop & Limits Wiring...

« on: January 18, 2014, 01:11:50 PM »

Regarding the controls circuit, would a 24v loop with the limit switches in it, connected to a small relay which has it's contacts connected to the BOB provide enough isolation?

This would give a relatively high current control loop (more than logic levels) and the relay would be wired fail-safe I.e. energised until a limit switch is hit or the e-stop pressed.

2604

General Mach Discussion / Re: E-STop & Limits Wiring...

« on: January 18, 2014, 10:51:39 AM »

Thanks, so I can daisy-chain the limits and use one input, then another input for the E-stop which three inputs free for THC if I go for it.

Screened cables definitely, star grounding and so on.

Will look into 24v control circuit too with opto isolators, never good taking a 5v PC supply line on a round trip of a machine

2605

General Mach Discussion / E-STop & Limits Wiring...

« on: January 17, 2014, 06:57:13 AM »

Hi all, first question, a bit basic

I am building a CNC plasma table and as I have never used CNC before, its a learning curve.

Reading the forums and the manual, I have gained some insight into the wiring methods to use for limits etc, but want to check I have the facts right...

There are only 5 inputs available (1 LPT port),
I can daisy-chain the limit switches (2x, 2y, 1z) and only use 1 input,
The E-Stop is on its own input, or can it be daisy-chained in with the limits?

If I later add THC, I believe it will need 3 inputs (Up, Down, Arc OK)?

In Mach3 I can use the limits as soft-home switches too (with the caveat of making sure the carriage is off the limits before homing)

With the E-stop in the limit chain, this setup will now use all 5 inputs, am I on the right track??


Many thanks

Dave

2606

Mach4 General Discussion / Re: New people welcome !! Come in here and introduce your self!

« on: January 16, 2014, 06:08:25 AM »

Hi all
new member here, I'm building a small CNC plasma table and never used CNC before

Started working my way through the demo version of Mach3, wow!

Lots to learn there, is there a section anywhere on using Mach with plasma's


Dave