Thread: G540 Help, old dog new trick.

You position the switches so that the machine smashes into them or so that they smash into a part of the machine and It then knows that it has reached the limits of its permitted travel.

My X axis ones are located under the moving crosspiece and they bash into the upright steel legs to tell me that the end has been reached.

Bob Willson

G'day Pete,

I use a G540 and Bob is right. You are also correct about needing a switch for each end of each axis, but these are usually connected in pairs, hence the 4 inputs for the 4 axes on the G540.
Because I'm such a tight ass all my switches are micro-switches recycled out of dead microwave door interlocks (up to 5 in some ovens).
Mine are all Normally Open wired in Parallel to ground in pairs. Actually I only use one on the top of the Z axis as a down limit really has no use as tool height changes often.
The forth input is used as a probe input for height referencing the plasma torch, and eventually will be used for a tough plate in my router profile as well.
All axes use the switches for both Homing and Limits in Mach3.

I feel I may be rambling so I'll stop now and see if you have more questions.

Cheers,

Tim.

Oh no dont stop rambling it is making sense to me. So 2 switches on each axis connected into the same input. So these switches act as home switches also ?
I didnt know that the 4th input could be used as a tool height setter.

Thank you very much.

Regards Pete

Hey Pete, if you are using Mach3 I can give you a quick 'how to' for setting the home and limits.
One direction is limit and the other is home for each axis. You choose where you want home to be and tell it to go that direction until it sees the switch input.
Let me know if you are using Mach3 and NO or NC switches and I'll help where I can.

Cheers,

Tim.

Is there a reason your worried about only 4 inputs?

Not trying to muddy the waters too much, I thought the same while building a plasma machine for a mate recently, however, if it is a huge issue, there are ways around limiting the inputs. It is possible to gang all switches to one input, although not recommended. Acting like limit switches you will have the machine go into an E-Stop State, then for homing, it is possible to clarify and make sure each axis homes one after the other so it knows which axis is moving and when it triggers will set that axis to the home co-ords.

Daniel

P.S The switches are all wired in series and act as both the limits and homing.

I'd recommend having a look at this pdf from peter's website:

http://www.homanndesigns.com/pdfs/EN010_V8.pdf

It's a very simple wiring diagram that also includes the homing / limit switch configuration. I know I refered to this many times when wiring up my control box.
It shows how you can wire all the switches into one input as described above.

Regards,

Row.

Now that it has sunk in I will wire 2 switches per axis into one input, so 3 axis into 3 inputs. Sorry I just thought that each switch would have his own input. Now I have to find some cables for between the motor and controller, I see that Homann has some but I found them after I already placed my order, Can I use cat 5 network cable?.

Regards Pete

Hi Tim I will be using Mach 3 and NO switches.
Thanks again for your help Tim.

Regards Pete

Originally Posted by Thunknker

Hey Pete, if you are using Mach3 I can give you a quick 'how to' for setting the home and limits.
One direction is limit and the other is home for each axis. You choose where you want home to be and tell it to go that direction until it sees the switch input.
Let me know if you are using Mach3 and NO or NC switches and I'll help where I can.

Cheers,

Tim.

Hey There Pete,

Sorry about the delayed reply.
The limit switches will need to be wired in parallel ie. one side of each switch goes to ground either on the G540 or your power supply. The Homann site and Gecko have good wiring diagrams.
The other side of the switch is connected to the other switch on the axis and then to an input on the G540 (pins 1-4).
You can join all the grounds together on the machine eg X axis and then you only need a 4 core cable back to the G540. 3 inputs and 1 ground.
Mine is wired Pin 1 X, Pin 2 Y, Pin 3 Z and Pin 4 Probe. These are important to know because they relate back to the port pins 10, 11, 12 & 13 that Mach will see.
Next download the G540 xml file and install it in Mach3 and create your profile. THIS IS IMPORTANT, I skipped this the first time and wasted a lot of time before going back and doing it right.
In the main Mach screen open the CONFIG tab then PORTS and PINS from the drop down and then the INPUT SIGNALS tab. Enter the values for the axes and tick the active low column as the switches switch to ground. These should be same as mine unless your axes are connected to different pins on the G540.Next apply the settings, and close the tab. Now if you should be able to open the diagnostics tab and switch the switches and see the corresponding leds light up.

Open CONFIG then HOMING/LIMITS. Set these up as you have your machine configured. Mine is a little different as the X and Z home to ++ and Y to -- a little trial and error will soon sort it out.
Jog around first to get a feel for what direction is what on each axis and when you are comfortable with your settings hit REF ALL HOME.

Hope this helps and the screen shots attached should simplify it.

Cheers,

Tim.

Thanks Tim you just saved me allot of time. Can you tell me what they mean by this in the G540 instructions. I am following Peters PDF on G540 wireing. As in esop disconnects power to the Power supply and a switch between pin 10 and ground.


CAUTION! Never put a switch on the DC side of the power supply! This will damage, if not destroy, your drive due to a current inrush when the switch is first thrown.

Regards Pete

There are two parts to that e-stop system. One connects pin 10 to ground with a NC switch (referred to on the schematic as ENABLE SWITCH) this is low voltage, and the other is also NC on the active of the A/C power to your power supply (240v).
This is probably a good idea and could easily be done with one mushroom switch and 2 NC contacts, but I am only using the switch to pin 10 and if activated, this cuts power to the motors as well as my router/plasma since they both run off relays driven by the G540 so I am comfortable with this setup but you can never be too safe.
I included a screen shot showing the pin settings for the e-stop in the previous post.

Cheers,

Tim.