Thread: G540 & CNC Build

A question about limit switches. If you're just jogging the machine and hit a limit switch, doest it stop? And if it does, how do you then get off the switch?

Brad.

Originally Posted by spidey4fun

A question about limit switches. If you're just jogging the machine and hit a limit switch, doest it stop? And if it does, how do you then get off the switch?

Brad.

Yes
On the settings page if you tick the "Auto limit override" feature then the process to get off the limits is
Press "Reset"
You can then jog off the limit but at only about 20% jog rate.
Once you are past the limit stop joging and this resets the jog speed to full.
Jog again at normal speed.

OK. I've wired one in and can see it "on" in the diagnostics. But how do I get it to actually stop the steppers from doing their business?

Brad.

Sorted... the x++ x-- etc... need to be checked and all set to pin 10 in my instance being input1.

Another question.. when you hit the limits is there any way to leave an enable pin on? I have my power supply to the VFD enabled when I turn the contoller on, and I dont want it to turn off when I hit a limit switch.

Brad.

Hi Brad
Do you mean that you have the 240 volt supply enabled through a relay to your VFD? If so, then I really don't think that this is a good way to wire it up.
The VFD would be better powered up from a separate external switch that can be independently switched on/off manually.
I realise that it seems more sophisticated to have it all powered up automatically when you turn on the system but I would much rather have physical control over that piece of equipment with just the power to the spindle being controlled by Mach.
Others may think differently.

Bob

Hey Bob, Yeah that's exactly how I have it set up and Im thinking I might just do that. I guess there's also less chance of things going wrong... like if the relay packed it in half way through a job.

A question on the limit switches. My G540 has 4 inputs. Is it better to use them all for the X & Y axis switches or just use one input and wire them in series?

Brad.

I with bob on this sometimes its cool but it leaves a lot to go south real quick also you can end up wasting a lot of time playing around and trying to get it right when you could be starting projects already.

Kiss = one switch less to go tropo.

But if Rod lived in Brisbane I am sure both Bob and I would be very happy campers.

Originally Posted by spidey4fun

A question on the limit switches. My G540 has 4 inputs. Is it better to use them all for the X & Y axis switches or just use one input and wire them in series?

Brad.

I always do the in series but then if your not going to use them for anything else well it wont hurt but either way no big deal besides losing the inputs if you dont go in series.

Did I make any sense then been stating work at at 5am and by about 5pm the wife cant understand me.

I would tend to put the X on one pair of switches and the Y on another.
Not really necessary but I like to keep things separate.
Another way is to only have one switch for the x and one for the y and have them operated by a sticky out thing.

OK... I've thought about the 'sticky out thing' idea but I bought a bunch of switches from China and figure it's just as easy to place one and each end. I think I'll just do the one input series thing.

Onto the crazy stuff..... my 24v DC motor / gearbox, chain and 5 sprockets arrived today.. Time to try motorize the movement of this table. I think I'll get a separate power source for it. Im not an electronics guy so this will be interesting.

This looks the ticket....

24V 4A Household Electric Power Supply Voltage Module (eBay item 320599697005 end time 05-Nov-10 07:14:28 AEDST) : Business Industrial


I ummed and arhed about buying the controller but they wanted $250 for it and I may be missing something.. but reversing the wiring the drive it up and down sounds like a fun controller to make.. any advise on parts from you electronics guys will be greatly accepted.

These bearings will sit atop thrust bearings and I'll mill a bracket to sit them in.



The motor / gear box.. This will simply bolt to the frame. Unless Im missing something, I should be able to just turn the sprockets till the chain is tight then tighten the grub screw to hold them in place. Gearhead is a 80mm 150:1 ratio so it doesnt rotate too fast.



Brad.

With maybe this....

24v DC LED dimmer adjustable brightness controller USA (eBay item 140462807725 end time 06-Nov-10 13:12:39 AEDST) : Home Garden

with this...

30 Amp Toggle Switch Polarity Reverse DC Motor Control (eBay item 360100135670 end time 11-Nov-10 12:30:00 AEDST) : Business Industrial

with..

http://cgi.ebay.com.au/NEW-Genuine-D...item3f032283cd

Brad.

Im thinking I can use the 240v output controlled by the G540 / relay to supply the power to the DC motor to rise and lower the table. This way I can use the inputs on the G540 for limit switches on the table height, and cut the power if I push the table to high / low.

Brad.

That all looks good Brad.
The only thing I would check is that the power supply still supplies 4 amps at 240 volts.
I know it says that it does, but it also says that it supplies this current at 110 volts as well.
You seem to have thought it all out quite nicely
Bob

I just tried the motor again and with the 150:1 reduction I doubt I'll need the variable voltage, as it's turning pretty slow and the limit switches will stop any mishaps.