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Author Topic: X Limit switch challenges  (Read 7323 times)

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Offline Davek0974

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Re: X Limit switch challenges
« Reply #10 on: February 23, 2014, 03:48:41 PM »
Sounds like you either need to make the switches NC or flip the setting in pis & ports so that it is active low or the opposite of what is set now.
Bridgeport Mill, Mach3 V062, CSMIO-IP/A controller, AC Servo Drives.
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Offline Fastest1

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Re: X Limit switch challenges
« Reply #11 on: February 23, 2014, 07:42:06 PM »
Hi, i am new to cnc and have a problem i need some help with please. I need help with my limit switch problem?
I`m new to cnc and this forum, i have built a router and controller but can only get it to work without limit switches pluged in.
My settup,
4 steppers, one slaved to the y axis.
E stop wired NO on pin 10
limit switches, 2 each axis all 6 wired NC in series on pin 11. Active low.
The problem, the nachine will only run if the limit socket on my controller is not pluged in as soon as i plug it in even with machine idle but under mach control  the reset button comes on and advises limit activated.
I have tried limits active high, no result.
i am getting very frustrated with this, the machine runs well without the limits pluged in but i do not want to run the risk of machine damage if i get a problem, i also want to use the same switches for homing but i need the limit problem solved, new to this so to solve one problen at a time.

Hope i can get some help.
Best wishes to all.
Billy

Have you changed the debounce setting?

Try installing a value of 1000 for starters. If it works, try 500, keep going less and less. Switches especially cheap mechanical ones are prone to bounce. Mach sees this as a trigger. If you lengthen this time (debounce) the signal must be present for the set time to be recognized. Try this first.

It could also be a ground issue but more on that later.

Do not switch to an NO set of switches. NC is the safest way and will come to a halt if ANYTHING in that circuit should fail. Better safe than sorry.
« Last Edit: February 23, 2014, 07:43:41 PM by Fastest1 »
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
Re: X Limit switch challenges
« Reply #12 on: February 24, 2014, 07:08:19 AM »
Hi, thanks for your reply.
Limits are in series and NC config ticked for active low
E Stop now changed to NC config ticked for active low

On screen E Stop flashing on Message External E Stop Requested
Tried debounce at 1000> 500 no change

Cannot get off E Stop to run the machine.

Billybob

Offline Fastest1

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Re: X Limit switch challenges
« Reply #13 on: February 24, 2014, 08:50:32 AM »
   These are 2 different set of problems.

   First lets get the EStop sorted. Are you sure your EStop is using NC contacts (the contacts are available separately and in both configurations). If you untick the "active low" does the EStop requested error go away? If so leave it that way until you get some new contacts or EStop button. Personally I have had this issue too. I now order my EStop switches with 2 sets of NC contacts. I use 1 set for the latching feature of my contactor and the other set for the EStop within Mach and my controller. My computer is powered upstream of the contactor so it never loses power. The pressing of the EStop kills all power to the machine at that very moment AND triggers Mach into a fault/EStop condition.
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
Re: X Limit switch challenges
« Reply #14 on: February 24, 2014, 12:06:21 PM »
Hi Again,
My e stop has 2 x sets of contacts, one for NO (green) and one for NC (red),  wiring connected to NC. IT is not making any difference if i untick active low makes no difference Estop request still on.
I am only using the e stop to stop the machine in Mach.
New machine and controller.
Regards Billybob.

Offline Fastest1

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Re: X Limit switch challenges
« Reply #15 on: February 24, 2014, 12:32:26 PM »
BB,    First go back thru the diagnostics. It sounds like the switch might be wired correctly but not the BOB.

   Which inputs are you using? pin 10 port 1?
   Does 1 leg of the EStop switch go to the ground of the BOB and the other leg go to pin 10? Try a jumper for a test. If that works then suspect your switch and or wiring.

   Also, you say you built your router and controller. Controller from a kit? Hobby Cnc?

   If you can, post pictures with your cell phone. Some of us are much more visual.
« Last Edit: February 24, 2014, 12:35:22 PM by Fastest1 »
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
Re: X Limit switch challenges
« Reply #16 on: February 24, 2014, 01:40:31 PM »
Hi,
Bob is wired to port 1 and pin 10.
Out from pin 10 to one side of the switch then from the other side of the switch to the ground of the bob. This ground shared with another ground.

The cable is twin core shielded.
I have tried grounding the shield to the steel enclosure through the plug, also grounded it direct to the bob and also grounded it to the earth terminal inside the case all gave same result.

I built the controller from components i picked up in a few places. I have built a controller before, a few years ago exactly the same and it was fine, but i droped out of the cnc thing due to health problems, back fighting fit now so at cnc again. I`m in the UK so its evening now, i`ll try and take a few pics tomorrow
Best wishes.
Re: X Limit switch challenges
« Reply #17 on: February 24, 2014, 01:45:50 PM »
Hi Billy,
  Can you double check your pin assignments in Ports and Pins, Input Signals ?

Russ

Offline Fastest1

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X Limit switch challenges
« Reply #18 on: February 24, 2014, 09:04:08 PM »
Let's not suspect noise just yet. Leave the shield unconnected at both ends.

    Didn't you say you can't get your EStop to stop flashing? Let's put a jumper from pin 10 on the BOB to the nearest ground on that side of the board. Try active low checked and unchecked if need be. Disable all limit and home switches til step 1 is complete.
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
Re: X Limit switch challenges
« Reply #19 on: February 25, 2014, 07:14:37 AM »
Hi Fastest 1,
Disconnected my estop. Disabled all limits.
Connected jumper ditect from pin 1 to bob ground.
Can reset estop when active low box un ticked. (X in box)