I am in the process of testing a new machine with the xPro and have been receiving the following messages back from the controller: ALARM: Hard limit. This typically happens when I am running the spindle, although not always. The spindle has it's own power supply and speed controller. I do have hard limits enabled but when this message occurs none of the limit switches are closed (verified with my meter) and typically I am not even close to the limit switches. 1) is there a way i can tell the xPro to display which limit(s) it thinks caused the alarm? 2) are there other causes that will raise the ALARM: Hard limit error? Things I have done: changed the ustep for x and y (see $100 and $101 below), replaced all limit switches, ran shielded wire for the limit switches, rerouted limit switch wiring to separate from motor leads, ac power, etc. The board is running Grbl 0.9i, connected to openbuilds stepper motors that came with c-beams and I am using UGS v1.0.8 to push it around. >>> $$ $0=10 (step pulse, usec) $1=255 (step idle delay, msec) $2=0 (step port invert mask:00000000) $3=0 (dir port invert mask:00000000) $4=0 (step enable invert, bool) $5=0 (limit pins invert, bool) $6=0 (probe pin invert, bool) $10=3 (status report mask:00000011) $11=0.020 (junction deviation, mm) $12=0.002 (arc tolerance, mm) $13=0 (report inches, bool) $20=0 (soft limits, bool) $21=1 (hard limits, bool) $22=1 (homing cycle, bool) $23=0 (homing dir invert mask:00000000) $24=25.000 (homing feed, mm/min) $25=500.000 (homing seek, mm/min) $26=250 (homing debounce, msec) $27=2.000 (homing pull-off, mm) $100=100.000 (x, step/mm) $101=100.000 (y, step/mm) $102=200.000 (z, step/mm) $110=500.000 (x max rate, mm/min) $111=500.000 (y max rate, mm/min) $112=500.000 (z max rate, mm/min) $120=10.000 (x accel, mm/sec^2) $121=10.000 (y accel, mm/sec^2) $122=10.000 (z accel, mm/sec^2) $130=200.000 (x max travel, mm) $131=200.000 (y max travel, mm) $132=200.000 (z max travel, mm) I am at a loss, any advice would be appreciated. Thank you, Justin
Sounds like false triggers from noise. Try reversing your limit switches from NO to NC and changing $5=1. Here's a blog about simple line filters http://m.instructables.com/id/End-Stop-Limit-Switch-Problems/ And another discussion on false triggering;https://www.google.com/search?site=...c.1.64.mobile-gws-hp..6.12.1013.3.CNHNfzLt3OY Joe
Hi Justin, Did you manage to fix the problem with false triggers from noise? I'm having the same issue.
Sorry a bit late to reply,I've also had a lot of problems with false triggers first I checked the resistance of all the limit switches and changed any that had a high reading also shelded cable was used to wire the limit switches the next thing was to change the power supply for a PSU that came out of a PC my thinking behind this is that a PC will need a clean power supply. I did buy some hall effect limit switches but only changed the Z to hall effect as I was not having any more false triggers
