Change homing speed on the fly

[Jeffsg605]

I've got a machine that is quite long on one axis (14'). I'd like to home this axis quickly, then when I get to the homing switch, back off and approach it again slower. I've tried using the command
exec.Writekey("axessettingscontrolY", "Homingspeedup", "2000");
// Home...
exec.Writekey("axessettingscontrolY", "Homingspeedup", "250");
// Back off and home again...

and while this does indeed change the .pro file, the changes don't seem to take effect on the actual machine. How can I change homing speeds when the machine is running?

Thanks in advance.

[dezsoe]

There's no reason to change the homing speed and home twice. You have an up and a down speed. First the axis travels to the home sensor with the up speed then with the down speed it comes off the sensor. The home position will be the point where the sensor deactivates. Set the up speed to fast, but slow enough to stop the axis with deceleration. Set the down speed to be precise.

Changing the profile makes nothing while the program is running. It reads the profile only on startup. While running you have to change fields and then press the Apply button. All can be done from macro or plugin, but don't forget that you cannot change any settings while the program is not idle.

[Jeffsg605]

Ahh, that makes a lot of sense, thank you!

[Dale]

But what if your homing sensors are not at the end of the travels?
Mine are in the middle, and depending what side the of the switch the axis is on, the speed to the homing switch is fast or painfully slow.

Would like to see more options for back-off the fine home just like probing,

Dale

[dezsoe]

You have 2 speeds: homing speed up and down. The first is active when the axis seeks the sensor, the second when the sensor is active and the axis moves away from it. When you start the homing and the sensor is active then it moves with the speed down feed. Normally the speed up is much faster then the speed down to find the sensor quickly but get a precise home position by moving away slowly.

[Dale]

Sorry, but that's not the way it works. At least on the latest test release.

Mine is set to 100 IPM up and 10 IPM down.

My homing sensors are on the middle of the travel. Because of this, the sensor (Inductive) is always tripped (Active) by a long metal bar on one side of the homing switch so that UCCNC knows which direction it needs to go to find home. Otherwise it crashes at the end of travel.

So, you see, if it's on the wrong side of the sensor, it takes forever to get to it.

I know most people put their sensors at the end of the travel, and then the current configuration will work for most. But for those with large machines, where the head normally parks near centre, it's advantageous to start homing near it's parking position.

[beefy]

Like many tables, my home switches are at the end of the axis.

However, when I turn my table on my Z azis may be at the far corner of the table. Even with the higher UP speed of the homing I don't rely on that to traverse all the way across the table to get to the home switch. Instead I simply jog at rapid speed to get me near the home switch, then do the homing.

Is that too much effort to do with your system ? You normally only home once after power on in any case.

[Spuds]

Like many tables, my home switches are at the end of the axis.

However, when I turn my table on my Z azis may be at the far corner of the table. Even with the higher UP speed of the homing I don't rely on that to traverse all the way across the table to get to the home switch. Instead I simply jog at rapid speed to get me near the home switch, then do the homing.

Is that too much effort to do with your system ? You normally only home once after power on in any case.

or, maybe just position the long axis(s) near the switch(s) prior to shutdown.