Homing & Limit Switch UNSOLVED MYSTERY! <solved>

[RJS100]

Thanks Shawn,

I did not think about this parameter. I am using a reference tool and setting the tool heights of the other tools relative to the reference tool. The default for Parameter 3 is "0". I have attached the notes from the manual regarding parameter 3. As I am new to this hobby, I am not sure of some of the references. It appears that bit 3 is "Unused for Mill". Any thoughts?

Thanks... Richard

[RJS100]

The more I think about this, I would probably want to always set a G59 position, so I am always referencing from the same X and Y position and using a Z heigh of 0. I see Parameter 3 bit 1, but how do you set the parameter value?

[RJS100]

I tried entering a number 4 into Parameter 3. I restarted the machine and homed it. For some reason the z-axis is now stopping about 1/2 inch higher than before. The flag is actually 1/2 inch higher with respect to the proximity sensor than before.

I went ahead and set a few tool heights, and all was looking good. The relative differences in tool heights were accurate.

I re-homed the machine and this time the z-axis stopped where it had been before, about 1/2 inch lower.

I am lost.

Thanks... Richard

[cnckeith]

post a fresh report.zip.

this stuff is all figured and dialed.

to help we need to see all the changes you made and understand what you are trying to accomplish from a good description/explanation.

[suntravel]

P3 =4 or 6 is ok for your type of mill.

But you must measure reference tool and other tools new after setting this parameter.

Uwe

[ShawnM]

Sorry Richard I don’t do tool offsets or tool measuring like a mill user so I’ll be of limited to no help with this new issue. Keith or Uwe will be able to help you with this.

[CNCMaryland]

The travel limits are your travels from your home position. Machine Coordinates 0,0,0.

You should not be going in the direction past the switch. Again, make one of the limits zero, and the other is the travel distance. Starting from the home position, move until you can't, look at the dro, that is your limit.

[RJS100]

Thanks Guys,

I have attached the fresh report.zip. Uwe, I did set Parameter 3 = 4, and re-measured the reference tool and two other tools. The relative tool measurements worked perfectly!

Since I was had previous issues with the machine homing to a consistent Z height, I happen to look at the z-axis proximity sensor and noticed that the flag was not stopping in the exact same place with respect to the proximity sensor.

The images below show the z-axis proximity sensor/flag, but you can see that it does not always stop consistently. I am not sure exactly what events take place when this happens. I have issued many tool changes previously to test it, and when doing so it always stopped in the exact same place. Coincidental or not, just after making tool height measurements, it did not stop in the same place (I did not take a picture of this event, but the flag was perfectly aligned with the face of the proximity sensor).

Do you think this is an issue with a Parameter setting or a defective proximity sensor?

Happy Thanksgiving.... Richard

[suntravel]

You have wired them in series, not recommended, because of the voltage drop. Maybe this causes inaccuracy.
Either wire NO in parallel, or use NC with one HomeLimit input for each axis (that is what I use with this kind of sensors, and it works 100% reliable)

Uwe

[ShawnM]

You have wired them in series, not recommended, because of the voltage drop. Maybe this causes inaccuracy.
Either wire NO in parallel, or use NC with one HomeLimit input for each axis (that is what I use with this kind of sensors, and it works 100% reliable)

Uwe

While it may not be recommended it does work consistently when using 24v as the power source. Any lower voltage and you might have issues with voltage drop but I can say for sure as I always use 24 volts. I've used the same cheap, Chinese prox sensors and similar ones including Omron prox sensors for years in series to a single input with zero issues. I understand it's not "best practice" but it saves inputs when they are needed for other things. I don't think this is the issue because Richard states that the machine homes now with out problems. He can also manually jog the machine from home to soft limit without issue.