Hi Folks,

I just upgraded my system due to a low speed/feed problem I discovered after I finished building the CNC router. I now have a Hobby CNC board and 200 oz. motors with a 35V power supply. I have also wired up my home/limit and e-stop switches this time but I am having problems getting things set up in TCNC V4.01. Can someone give me some pointers as to where I have gone wrong. I can spin the motors if I go into the jog screen and toggle the limits to 'off' (and I get good speeds) but with the limits toggled to 'on' I get no movement in 'jog' and no movement if I use the MDI screen. The 'Status Window' says 'Stopped' at the top and any attempt to move under the MDI screen says 'A limit switch is active'. When I hit the e-stop I get no indication on the screen that the e-stop has been hit but thankfully I have the e-stop wired through a relay that turns off all power to the board so the motors do stop as they should. I have tried toggling the 'active high/low' settings and toggling the limits to 'enabled/disabled' but it makes no difference to the operation. I also have the 'Use home as limit' option checked too. I have been making sure I reset the ports after making any changes.

This is my hardware set up:

Three limit switches wired NC in series connected to pin 13.

Three home switches wired NO to individual pins as follows:

X home - pin 10
Y home - pin 11
Z home - pin 12

E-stop wired NO to pin 15

This is my software set up:

Use home as limits - active
E-stop - enabled - pin 15 - active low
Limit switch - enabled - pin 13 - active low
X home - enabled - pin 10 - active low
Y home - enabled - pin 11 - active low
Z home - enabled - pin 12 - active low

It would appear that for some reason TCNC is seeing a tripped limit somewhere but for the life of me I can't figure out where and changing parameters seems to make no difference. I have checked the physical pin wiring and the switches themselves to make sure those are ok and they all check out as fine.

Any help/pointers greatly appreciated.

Larry

Larry,
See my response over on TCNC group on yarpoo

Larry,
See my response over on TCNC group on yarpoo

Thanks Art I did get it via email.

Larry

Hi

It took me a few days and some bent limit switch tabs before I
finially got things right.

Have my home swithches set up NC, 1 for X (on 10), 2 for Y (on 11), 3
will be my Z (on 12)(pending Z switch install). I have all limits NC
and in series (on 13).

Using Home switches as limits was on.

I had to togle limits off in Jog to move... not right.
I had to shut off Home as Limits to move in MDI and have limits
work.... not right.
But then I had no limits on Home side of machine.... not right.

Brain Teaser!!!!!!

I picked up on something I read in one of the posts about I/O 11 was
normaly opposite of the rest. So I went into the turbocnc.ini and
change the state to 'normal high=NO' and everything went to working
correctly. I don't remember which post on the I/O 11.... as I have
read so many... but thanks to who wrote it..

The limits work like they are surpose to and the machine homes on the
money.

I found that when a limit tripped I had to go to the Jog and toggle
off the limits to back it off the limit switch. Don't forget to
toggle the limits back on after moving off limit switch. I sure have
tuff limit switches....found out the hard way..... ;-)

Hope this will help.

I posted this on the Yahoo Group as well.

Thanks I did get it via email from the 'other place'.

I have rewired my system to pairs of switches per axis wired NC with each axis going to a separate pin and 'use home as limit' turned on. I now have the limits working correctly but it will still not home at all. I have sent the .ini file to Dave at TCNC and we will see where we go from here.

Larry