Homing Not Reading Zero

When I power up the Masso control then home the machine the position doesn’t zero. It reads varied positions, both positive and negative. When I use the touch plate to position the start point of my work piece the correct position is given on screen, according to the grid laid out on the spoil board. I go to the work piece start position from the touch screen and the machine goes to the correct position. My question: is it a malfunction that the positions indicated don’t zero during initial homing? Seems a stupid question since the work piece start position is correct, I know. I’m concerned about future events.

I’ve spent time looking through homing subjects within the forum and haven’t seen this addressed.

Thank you in advance helping this newbie.

What values are you seeing?

The values are not so varied, now that I observed the last instance. The values are negative distances from my last origin point except the Z value. Z value is positive from the touch point. When I go to Origin Point without using the touch plate the machine returns to the last origin point. This happens after shutting down and restarting the Masso Controller.

Are you reading machine positions or work positions?

If you are talking about homing, the machine coordinates for your XYZ should all read 0.00.
The machine coordinates and the work coordinates (G54 default) should all show zero on screen at this time.

My apologies if I am not fully understanding the use case you are describing.

After I home I can use the MDI to change to any of my G5xx work offsets, and ‘Go To Work Origin’ will take me to whichever is currently active. These are saved, so even after a shutdown/restart/rehome I can repeatedly go to any one of these - I use this for my fixtures. I never worry about Z height varying as I zero Z before machining each time anyway.

I’m reading machine position when homed.

I have home set to zeros in settings. After resetting G54 to zeros, the work piece origin point is placed into the G54 coordinates and saved. There’s something in the settings I guess. Thanks for helping me think this out. The problem is not solved and I appreciate any suggestions.

So the machine coordinates do not always read zero after homing?

Also I find that if I zero the machine anywhere else in the work area, this becomes the new zero for G54 until you zero somewhere else again, for instance I use G55 for my origin to be the lower left corner and G54 to set random origins.
Hope this helps.

My default home automatically sets to G54, and I always leave it dedicated home.
The other offsets I use/reuse for fixtures etc.

The newer software version will add more offset options, but I am not ready to make the switch until all the updates have passed Beta testing.

In LinuxCNC, the selected Coordinate System number (G54–G59.3) is persistent. That is why many g-code programs include a preamble to reset it. I don’t know how the Masso behaves here on homing.

The coordinate system selected is stored in parameter 5220 and can be checked by entering this command into the command entry field of the MDI:

(debug, Selected Coordinate System is: #5220)

According to the RS-274 Standard, this must contain a value from 1 to 9.

My point was that the controller puts my origin point position into the G54 location. Aren’t I supposed to input the location into G54 data?

My Masso defaults to G54 when it homes. If I want to then use G54 for an offset, for a job for example, I would need to re-zero at the new position while still in G54.

After more time spent operating my instrument I think I understand what is happening. When I set my work piece and probe it the coordinates are stored as G54 location. Homing only tells the processor where the X Y and Z motors are starting from in order to send the bit where it needs to be. I mistakenly thought that homing not only told the processor where X0 Y0 and Z0 are, it would also reset the on screen readout to zeroes. If I fasten two fences on the front of my work piece and on the left of my work piece, after probing the lower left corner, I could place all future projects against the fence and only probe for Z. If I have a tool setter and auto tool zero is set when homing, would I even have to probe for Z, assuming my run automatically called for a tool change?