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Author Topic: Getting "-----ESS: Limit Switch triggered on" at bootup of mach4  (Read 437 times)

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Offline jevs

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Any idea why I get "-----ESS: Limit Switch triggered" on  at bootup?
Nothing seems to be triggered, and homing works fine.
If you just ignore this, things seem to work fine, but it is annoying seeing it every time like there is something wrong...
Re: Getting "-----ESS: Limit Switch triggered on" at bootup of mach4
« Reply #1 on: September 02, 2019, 05:08:23 PM »
Does your setup think the homing switch is a limit switch? Try setting soft limits correctly and turning them on.

Offline jevs

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Re: Getting "-----ESS: Limit Switch triggered on" at bootup of mach4
« Reply #2 on: September 02, 2019, 06:56:04 PM »
Does your setup think the homing switch is a limit switch? Try setting soft limits correctly and turning them on.

No and soft limits are on and set correctly. I have separate limit switches and homing switches.
The homing switches are a bit in from the limit switches at the homing side of the axis. The Z homing is real far from the limit switch because it has to move above homing to do the tool change. It should never hit the limit switches, but if you did hit the limit switches by doing something wrong your dead in the water because they kill everything until you hold down my limit override switch to bring it off of them. It should never hit the actual limit switches during normal operation unless something is done wrong. 
When it says this stuff on boot up, no switch is active. From what they said on the Warp9 forum this could just be that it sees something active during the boot up sequence before it is all done initializing, but is not really a problem since it is not really an issue once it is all booted up and homed.

From the Warp9 forum:
"......Depending on your wiring, your specific limit switches and your break out board, your limit switch signal may very well be active (as supplied to the ESS input pin) even though your limit switch itself may not be activated. A lot depends on the power up sequence and states of that other hardware. That being said, there is no issue with just ignoring that message at startup,and as soon as you press the enable button that message will be gone (assuming you are using v246 of the ESS plugin)."
Re: Getting "-----ESS: Limit Switch triggered on" at bootup of mach4
« Reply #3 on: September 02, 2019, 06:59:24 PM »
ok, so what message you get when the limit is actually triggered?

Offline jevs

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Re: Getting "-----ESS: Limit Switch triggered on" at bootup of mach4
« Reply #4 on: September 02, 2019, 07:37:53 PM »
This has to be done intentionally with soft limits off or no homing but.....
if I intentionally run it thorough the home switch and on past to hit the limit switch:
Home switch X Home tripped!
Limit switch X ++ tripped!
Limit switch Y ++ tripped!
Limit switch Z ++ tripped!
Limit switch X -- tripped!
Limit switch Y -- tripped!
Limit switch Z -- tripped!
-----ESS: Limit Switch triggered on  Motor Limit 0++  Motor Limit 1++  Motor Limit 2++  Motor Limit 0--  Motor Limit 1--  Motor Limit 2--

Limits are all tied together in series. This is why you get all of these if any is tripped.

The messages I get at boot up from the ESS are kind of random also, it is not just the "----ESS: Limit Switch triggered on" It will sometimes say other things are tripped. It is kind of random. However it does not really affect anything because hitting enable clears it all and everything works. It all works fine after that and you home it. It is just a little annoying that the ESS flags this stuff until it gets itself communicating with Mach4 at bootup even though it is not real...
It would be nice if you could turn off any initial error flagging until Mach4 is fully booted and the ESS is in full communications. 
Re: Getting "-----ESS: Limit Switch triggered on" at bootup of mach4
« Reply #5 on: September 02, 2019, 07:55:18 PM »
are the switches mechanical or electrical?
why series them?

Offline jevs

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Re: Getting "-----ESS: Limit Switch triggered on" at bootup of mach4
« Reply #6 on: September 02, 2019, 08:17:25 PM »
This is the way the machine was made originally by Fanuc (for Pratt & Whitney). They are mechanically actuated "electrical" switches. They mechanically make or break the electrical path. They are industrial switches with the roller tips. This is all barking up the wrong tree though. The ESS reporting things being tripped has nothing to do with the switches or being wired in series. The limit switches do not need to be wired independently. The homing switches are though.

The ESS is reporting false states at initial communications presumably because of what I quoted from the Warp9 forum. I cannot say what is is actually on the pins where it is connected to the BoB at boot up. The BoB (Machmotion IO6) and the ESS are both powered up before Mach4 boots though. the ESS is powered from the BoB.

I am not sure this is anything that can be fixed. It may just be the way it is and ignore it. It does not affect any operation. I just don't like seeing the messages at bootup when they are not real. I would have to put a scope on the pins to the breakout board and try to capture things to see what the ESS is really seeing during this time. Even if I do see it, I don't know what I could do to stop it from reporting those until things are in full communications.
Re: Getting "-----ESS: Limit Switch triggered on" at bootup of mach4
« Reply #7 on: September 02, 2019, 08:39:19 PM »
Well, the ESS board is getting a signal that the limit switch is active on start-up. I doubt it's a random start-up state in the controller. If the limit switches are, in fact, series-connected then they must also be normally closed (and open when activated).

Hypothetically, if the switches have a bad contact (and a slightly resistive path to ground or Vcc), then that will allow the pin voltage to float and produce a seemingly random error. A loose (or resistive) switch connection would do the same thing.

You may also be getting electrical noise on start-up that feed into the switches. Check the machine ground connection.

Monitor the voltage on this pin. A DVM may work but will need an o-scope to see the transients though.

Offline jevs

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Re: Getting "-----ESS: Limit Switch triggered on" at bootup of mach4
« Reply #8 on: September 02, 2019, 09:42:57 PM »
I can test this theory pretty easy by just holding down my limit override switch at bootup. This switch shorts the limit switch pins right at the BoB. It is pretty new compared to the original limit switches and should produce close to zero ohms and no possibility of a floating or resistive connection.
I will try it tommorow night.

Offline jevs

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Re: Getting "-----ESS: Limit Switch triggered on" at bootup of mach4
« Reply #9 on: September 02, 2019, 10:07:17 PM »
I just went out and checked this. No difference. Making a dead short on the limit switch pins during bootup does not change anything.
It still gives all the limit warnings on bootup. The signal shows rock solid in the ESS diag and trips perfectly when opened while hitting a limit.
I see no issues with the limit switches.
 It could just be the way the ESS sees the BoB signal when mach4 first starts. Not sure....
I may stick my meter right on the pin at the ess and watch it to see what happens...
« Last Edit: September 02, 2019, 10:09:16 PM by jevs »