Hello Guest it is November 15, 2019, 02:11:58 AM

Author Topic: A Few General Questions  (Read 2315 times)

0 Members and 1 Guest are viewing this topic.

A Few General Questions
« on: January 01, 2016, 12:36:44 AM »
Kinda new to CNC, I built an OX clone CNC machine...been running a TinyG controller and Chilipeppr interface for a couple of weeks

Going to purchase Mach3 and a Gecko 540 VERY SOON...been reading all I can (including this forum) about Mach3...even dabbled with the screen designer...have run a lot of code thru the demo version! Anyhow...

Does Mach3 keep the motors locked at zero speed whenever it is active? If so, how do people operate, shut down Mach when not running the machine?

Home switches - my machine has two Y's, so I will have to slave to A axis correct? I think I read that you cannot series the home switches (to one input) with a slaved axis? So , if true, and I understand, I will use three inputs for the switches (X,Y,Z) and the last for my touch plate? correct?

Touch plate...my TinyG resets (to 0) the machine home when the touch plate is run...is this the way Mach works? I would thing a better way would be to leave the machine home (alone) and set the G54 Z offset to 0?!? How does Mach do it (Z axis touch plate)?

Thats all I can think of now, I thought I had a few more...

Thanks in advance...

Online Tweakie.CNC

*
  • *
  •  7,993 7,993
  • Super Kitty
    • View Profile
    • Tweakie.CNC
Re: A Few General Questions
« Reply #1 on: January 01, 2016, 02:30:11 AM »
I think Mach3 and the G540 would be a good investment.

The motors are locked when not in motion - you can also use an Enable signal which can be configured within Mach3 to either ‘lock’ the motors or ‘free’ the motors when in an Estop condition.
It is conventional to have Mach3 up and ready before switching the CNC machine on and the CNC machine is usually switched off before Mach3 is closed.

You will need 1 input for your slaved axis limit / home switches and 1 input for the other limit / home switches. Also 1 input for your touch plate and 1 input for your Estop (the Estop could be combined with the other limit / home switches but it is conventional to have it on it’s own input).

The Z axis touch plate has user configurable script (Cypress Enable) which is usually written to move the tool to a safe height after calculation and setting the Z axis DRO to a figure which would make the tool touch the work surface if goto zero is invoked.

Hope this helps,

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline ger21

*
  • *
  •  6,288 6,288
    • View Profile
    • The CNC Woodworker
Re: A Few General Questions
« Reply #2 on: January 01, 2016, 06:33:37 AM »
Quote
Does Mach3 keep the motors locked at zero speed whenever it is active? If so, how do people operate, shut down Mach when not running the machine?

This is not really a function of Mach3, unless your stepper drives use an Enable signal, and you wire those to Mach 3's Enable inputs.

Typically, when your drives are powered, they lock the motors. Some drives use current reduction to reduce motor heat when the motors are idle, but again, this is not a Mach3 function.

What I do, is start Mach3, and when it's running and out of Estop, I turn on the power to my drives.
To shut down, I turn off the power to the drives, and then close Mach3.

Your motors should never be powered when Mach3 is not running.

Quote
Home switches - my machine has two Y's, so I will have to slave to A axis correct? I think I read that you cannot series the home switches (to one input) with a slaved axis? So , if true, and I understand, I will use three inputs for the switches (X,Y,Z) and the last for my touch plate? correct?

A lot of people with limited inputs use one input for X, Y, and Z, and one for the A axis. your slave and master need to use separate inputs if you want Mach3 to square the gantry when homing.

Quote
Touch plate...my TinyG resets (to 0) the machine home when the touch plate is run...is this the way Mach works? I would thing a better way would be to leave the machine home (alone) and set the G54 Z offset to 0?!? How does Mach do it (Z axis touch plate)?

Mach3 has no default touch plate functionality. It's up to you to either find one or write your own. The vast majority (all that I've seen) just zero the Z axis (set the G54 (or current coordinate system) offset). Home position is usually set with a Z axis home switch, at the top of the Z travel.
« Last Edit: January 01, 2016, 06:39:23 AM by ger21 »
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: A Few General Questions
« Reply #3 on: January 01, 2016, 10:42:19 AM »
Thanks for the reply's and Happy New Year

Quote
A lot of people with limited inputs use one input for X, Y, and Z, and one for the A axis. your slave and master need to use separate inputs if you want Mach3 to square the gantry when homing.

Not sure I understand completely, to make Mach work do I need a fourth limit switch? if the gantry is square (when not running) and I run the motors always together, how would it get out of square (other than one motor missing steps, which I have not encountered?), and I think it would harder to get two limit switches aligned perfectly. Or do I just wire the single Y to the second input, that is X and Z in series on one pin, and the single Y on another pin?

If the second Y is slaved to the A, then why wouldn't a single switch on the Y control both motors?

Leslie
« Last Edit: January 01, 2016, 10:45:25 AM by leversole »

Online Tweakie.CNC

*
  • *
  •  7,993 7,993
  • Super Kitty
    • View Profile
    • Tweakie.CNC
Re: A Few General Questions
« Reply #4 on: January 01, 2016, 11:38:26 AM »

Ideally, a square gantry should always remain square but in practice it has been found prudent to use a squaring routine - limit switch data / information is contained in section 4.5 of the manual http://www.machsupport.com/help-learning/product-manuals/

Tweakie.
« Last Edit: January 01, 2016, 12:10:26 PM by Tweakie.CNC »
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline BR549

*
  •  6,916 6,916
    • View Profile
Re: A Few General Questions
« Reply #5 on: January 01, 2016, 12:39:58 PM »
The mechanical design of a gantry normally insures that it will not always remain square. UNLESS both sides are mechanically linked together as a unit each side has a HUGE mechanical leverage over the opposite side. So it is easy to pull it out of square.

(;-) TP
Re: A Few General Questions
« Reply #6 on: January 01, 2016, 01:19:29 PM »

Ideally, a square gantry should always remain square but in practice it has been found prudent to use a squaring routine - limit switch data / information is contained in section 4.5 of the manual http://www.machsupport.com/help-learning/product-manuals/

Tweakie.

Thanks for the link! Had not seen those! Gonna dive in reading!
Re: A Few General Questions
« Reply #7 on: January 01, 2016, 08:24:38 PM »
Just when I thought I understood! After reading thru the manual...here is what I was thinking...I need to install a second Y limit switch, wire XYZ limits to a pin, wire the second Y to its own pin, e-stop to a pin, and the touch plate to a pin (that's all 5)...when the Y is homed, it will use the XYZ Y pin, then use the extra Y to home the other side (slaved axis), did not quite understand this (it drives both motors to the initial switch, then only the second motor, which should just be off of the second switch?!?), anyway I got to this part in the manual (see attachment), and according to it, I can set it up like I have it now, using one Y switch to home both axis's?!?




Offline ger21

*
  • *
  •  6,288 6,288
    • View Profile
    • The CNC Woodworker
Re: A Few General Questions
« Reply #8 on: January 01, 2016, 08:49:51 PM »
Yes, you can home both master and slave to one switch by checking "Home Slave with Master" in General Config.

Quote
when the Y is homed, it will use the XYZ Y pin, then use the extra Y to home the other side (slaved axis), did not quite understand this (it drives both motors to the initial switch, then only the second motor, which should just be off of the second switch?!?)

No, when you have a separate switch for the master and slave, they both home at the same time.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: A Few General Questions
« Reply #9 on: January 01, 2016, 08:59:11 PM »
Thanks again! I guess I need to get the new drives purchased and get busy wiring things!