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Offline Hood

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Re: Strange Results
« Reply #40 on: December 11, 2009, 03:46:36 PM »
No, wiring polarity of a mechanical switch does not matter, sounds like your input pin is not working correctly, if you have another you can connect to try that.
Hood

Offline kolias

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Re: Strange Results
« Reply #41 on: December 12, 2009, 02:25:42 PM »
No, wiring polarity of a mechanical switch does not matter, sounds like your input pin is not working correctly, if you have another you can connect to try that.
Hood

I did try other pins, I switch the wires (Black & Red) and nothing worked, status line says (Limit switch Triggered). Switching the active low ON or OFF does not correct the situation and when I press the Reset on the screen it always has on the status line the same message (Limit switch Triggered).

I use the “Auto Set of Input Signals” on the inputs screen to set the limit switch and when I press with my finger the switch the message on the screen says “Select Next Signal” which means to me that the switch communicates with mack3.

Also I noticed that when the switch is connected the diagnostic screen has the light on Enable 1 OFF. When the switch is not connected the same light is ON.

Finally I decided to switch the connections on the limit switch from COM + NC to COM + NO. Now it works well and when I press the Reset it clears the status line message and when I move the Z axis down and trigger the switch the machine stops and by hitting the reset (after I move the trigger lever from the switch) it clears the status line.

With this setup, the Active Low for the Z axis limit switch is now ticked. My Estop is connected with COM + NC and the Active Low is not ticked. On the diagnostic screen the Enable 1 light is ON.

To me all seems to work fine now but I don’t understand why the limit switch must be connected with COM + NO and have the Active Low ticked and the Estop with COM + NC and have the Active Low not ticked.

I attach my xml file in case it is needed.

Nicolas


Nicolas

Offline Hood

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Re: Strange Results
« Reply #42 on: December 12, 2009, 07:06:21 PM »
The reason the Limits and E-Stop active state is different is because one is looking for an active Hi to signal a trigger and the other an active low and that is because you have one NC and the other NO.
 All are best set up as NC as it means if a wire breaks or a contact comes loose Mach will not know if you have them set normally open and you will only know when you are needing the limit to be seen and it is not.
I will have a look at your xml and see if I can find a problem but have you tried setting manually instead of using the Auto Setting?
Hood

Offline Hood

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Re: Strange Results
« Reply #43 on: December 12, 2009, 07:11:05 PM »
Just had a look at the xml and dont see anything glaringly obvious wrong, if you try NC again change the active state on the limits and also try putting 2000 in the Debounce Interval on the General Config page.

Hood

Offline kolias

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Re: Strange Results
« Reply #44 on: December 12, 2009, 10:49:40 PM »
Thank you Hood

Originally I did try setting the limit switch manually and since I did not succeed I used the Auto Setting.

I will give another try tomorrow to set the switch manually and change the active state plus put 2000 in the Debounce Interval. I will also try another switch just in case although I did check the switch with an ohm meter and worked good.

I do know that is better to have a NC switch as you explained but I keep wondering why my switch only works as NO

Nicolas
Nicolas

Offline kolias

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Re: Strange Results
« Reply #45 on: December 13, 2009, 10:52:07 AM »
Thank you Hood

It worked! I installed a new limit switch, just in case, connected between COM + NC, set the Debounce Interval to 2000 as you said and now it works fine.

BUT after a couple of minutes and without touching anything on the machine including the limit switch, the warning came on that “Limit Switch Triggered”.

What the Debounce Interval do?

Why the “Limit Switch Triggered” message came on again without touching the switch?

If it has to do with RF noise interference would it help if I ground the jacket the limit switch cable to my DC grounding bar where I have grounded the motor cable jackets?

Nicolas
Nicolas

Offline Hood

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Re: Strange Results
« Reply #46 on: December 13, 2009, 11:15:15 AM »
Ok it is as I suspected, you do have noise on your wires to the switches. Yes grounding the shield should always be done on any 5v signal wires as they are very susceptible to noise. Make sure you just ground at the control end and try and ground all shield wires to a single point.
 Hopefully once you have done that you can reduce the debounce interval to zero, although its not going to do much harm having it at 2000, just I prefer to not use it if possible. What it does is just filter the signal when it comes to Mach so that any signals less than the amount you have set are ignored, if you set 2000 that is only 2000 x 40 micro seconds, so its not a long time, only 0.08 seconds :)

Hood

Offline kolias

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Re: Strange Results
« Reply #47 on: December 13, 2009, 11:22:56 AM »
Ok it is as I suspected, you do have noise on your wires to the switches. Yes grounding the shield should always be done on any 5v signal wires as they are very susceptible to noise. Make sure you just ground at the control end and try and ground all shield wires to a single point.
 Hopefully once you have done that you can reduce the debounce interval to zero, although its not going to do much harm having it at 2000, just I prefer to not use it if possible. What it does is just filter the signal when it comes to Mach so that any signals less than the amount you have set are ignored, if you set 2000 that is only 2000 x 40 micro seconds, so its not a long time, only 0.08 seconds :)

Hood

Sorry Hood, when you say at the control end do you mean at the end where the limit switch is?

Nicolas
Nicolas

Offline kolias

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Re: Strange Results
« Reply #48 on: December 13, 2009, 01:08:21 PM »
Well I did ground the cable shield from the limit switch and connect it on a screw in the ground bar where I also have the grounds from the 3 motor shield cables. I assumed that the control end is where all my motor drivers and power supply unit are.

But it seems that grounding the cable for this linit switch made it worst because now I get the same message again “Limit Switch Trigered”. I played around with the Debounce Interval from 0 to 2500 but the message comes back although not instantly, takes about 3 – 5 seconds and when I reset it comes back again.

I will not disconnect this ground until you tell me to do so

Nicolas
Nicolas

Offline Hood

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Re: Strange Results
« Reply #49 on: December 13, 2009, 01:49:37 PM »
You would be better disconnecting it if it makes things worse, seems that you are creating more noise in the wires by having it connected, why I dont know :(
Hood