$H: Alarm: Homing fail w/ An unexpected command was completed by the controller w/ Java Exception

[toffuser]

Problem description

When sending $H to GRBL using UGS Platoform 2.0 nightly (Arduino UNOS with CNC shield) I get the error message Alarm: Homing fail after it moved for a while (Any axis, X, Y or Z)

Expected Behavior

It is supposed to reach the limit switch for any axis.

Actual Behavior

It moves for a while then after 10 seconds, it stops.

Steps to Reproduce the Problem

1. Open the program
2. Click on Home Machine
3. let the machine try to go HOME and FAIL

Specifications

Version

UGS Platform 2.0 - Nightly Build Mar 29, 2019
UGS Classic 1.0.9

Operating system

Windows 10

Platform

GRBL 1.1f

Other

The exception thrown in the UGS platform :

com.willwinder.universalgcodesender.AbstractController$UnexpectedCommand: An unexpected command was completed by the controller.
at com.willwinder.universalgcodesender.AbstractController.commandComplete(AbstractController.java:829)
[catch] at com.willwinder.universalgcodesender.GrblController.rawResponseHandler(GrblController.java:170)
at com.willwinder.universalgcodesender.AbstractController.rawResponseListener(AbstractController.java:850)
at com.willwinder.universalgcodesender.AbstractCommunicator.sendEventToListeners(AbstractCommunicator.java:222)
at com.willwinder.universalgcodesender.AbstractCommunicator.lambda$new$0(AbstractCommunicator.java:244)
at java.lang.Thread.run(Thread.java:748)

[breiler]

Could you post the settings for GRBL?

[AbySet]

Hey,
Sorry i'm a bit late but i have been through a same issue and i fixed it:

• Your problem is not a UGS one, it's actualy a hardware issue caused by IME troubles and it needs a noise filter.
• To solve this you should add a filter to your limit switchs wiring by adding a 4.7K resistor and 100nF capacitor and here is how to do it :

Notice that the 3 resistors color code shows a value of 1K but you have to use 4.7K as labeled (I did not do the schematic).

Hope this help.

[carneeki]

Adding to Aby's great answer, the 4K70 resistor colours are 4 band: Yellow (4) Violet (7) Red (x100) (any colour for tolerance, but gold is pretty common = 5%, brown = 1% and silver = 10%) 5 band: Yellow (4) Violet (7) Black (0) Brown (x10) (any colour for tolerance, but gold is pretty common = 5%, brown = 1% and silver = 10%) [image: image.png] Image courtesy of https://www.electronics-tutorials.ws/resistor/res_2.html Keeping the pull up resistors and capacitors physically close to the Arduino inputs and with short wires is helpful to minimise interference - we can think of wire acting as antennas picking up cruft, and the capacitors are low pass filters that only let "slow changing signals" like buttons or switch presses into the microcontroller.

…

On Sat, 13 Apr 2019 at 18:25, AbySet ***@***.***> wrote: Hey, Sorry i'm a bit late but i have been through a same issue and i fixed it: - Your problem is not a UGS one, it's actualy a hardware issue caused by IME troubles and it needs a noise filter. - To solve this you should add a filter to your limit switchs wiring by adding a 4.7K resistor and 100nF capacitor and here is how to do it : [image: Limit_Swiths_Wiring] <https://user-images.githubusercontent.com/35888124/56076846-c40b4180-5dd5-11e9-926b-f47a0220fcb5.png> Notice that the 3 resistors color code shows a value of 1K but you have to use 4.7K as labeled (I did not do the schematic). Hope this help. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1208 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAdYqCBNMVYx6dyVNT1YyWkdTV6hfHosks5vgZRvgaJpZM4cS_tV> .

-- Adam "carneeki" Carmichael p: +61 415 37 1990 w: http://bigneek.com e: carneeki@carneeki.net i: 2207644

[toffuser]

Abyset is right!

I also shielded my limit switch cables. Make sure to put them far away from the cables used for the motors.

[breiler]

@toffuser, was this resolved?