Save last known zero point and retrieve after power down

Easel Feature Requests
1

For long carves, going across days, sessions, power on/offs.

Request the ability in the carve modal to select the 0 position of a previous carve from a previous session. Even going across power on/offs.

If this is not possible, then request a notification or message in the ‘carve complete’ and ‘stop a carve modals to display the 0 position/ x, y coordinates of the current carve. At least this way, we can come back the next day and jog the machine to the previous day’s 0 point.

Better yet, have the ability to pause a carve and restart where you left off.

2

@TM1

Part of this is already possible for part of what you want…inside the GRBL firmware itself…as long as you have machine homing switches installed, have Homing enabled, and use the Homing feature.

When the machine is “Homed” on initial started (or at any time for that matter), The GRBL firmware marks the (X, Y, Z) coordinate where the homing switches are activated as the “Machine Home” position. All movements and marked locations such as the “Work Home” position that you set when starting a carve using Easel are nothing more than offsets from the “Machine Home” position.

So, using this you could carve the same piece, given the new stock is in the exact same location, over and over again across power cycles as the “Work Home” offsets are stored in the EEPROM of the controller each time they are set. All you would need to do is perform a machine homing cycle after powering the machine up. This also work for carving separate features on the same part using different workpieces or NC files.

The one thing you can’t do is stop a carve mid-way through and then restart it at a later time. This is because the majority of grbl gcode senders are not processing information from the controller about what it has/has not completed…all operations are sent and stored in a queue within the firmware and Easel has no idea where the machine would have gotten to in that queue.

I mean you could do it if you really wanted to. You would have to download the NC file, and you would need to be very proficient at manually editing the NC file to accomplish this. You would basically have to stop the carve. Download the NC file and edit it to remove everything up to the command just prior to the last one completed and add your own move commands between that and the normal start up commands. Since you would not know where exactly the grbl firmware stopped either, this would be a slight guessing game. I do not recommend this at all…

{:0)

Brandon R. Parker

3

This feature exists, and it is performed exactly as you’ve expressed it in this sentence; Pause and then Restart. So long as you leave the cnc turned on and the PC connected, the Pause and Restart works flawlessly.

What Brandon Said… this is what the “Use Last Position” function does. . .
Reference the Bulletted items found here specifically the very last bullet point and the sentence following…

4

The feature request is after a power off.

The ‘use last position’ doesnt work after a power off. It does work if and only if the controller was not powered off.

Would like to start a carve from yesterday’s 0 point after the controller was powered up today. Whether or not the router was moved.

5

Yes it does. As long as you have homing switches.
That information is stored in non-volatile memory on the controller.

1 Like
6

Are you saying that one can turn off the controller then turn it on the next day and return to the previous days work 0 by homing the machine?

I have homing switches, but they are not setup in easel.

When i tried the ‘use last work 0’ after restarting the machine it just ran the zcarriage up to front of spoil board and stopped.

Im not understanding some things here.

7

Yes! This is exactly what we are saying.

You need to enable homing on your machine. Perform a machine homing cycle when you start your machine up. Then when you set the Work Home position using Easel, this is just stored as offsets from the Machine Home position. After powering the machine off/on again, perform the machine homing cycle after the power-up. The Work Home offsets are still stored in the EEPROM (non-volatile memory - a.k.a. persists across power cycles). When you go to carve, simply select “Use Last Position” when Easel prompts you.

The reason for the crash is the machine does not have a Machine Home reference without homing being enabled and the homing sequence being performed.

You can enable Homing by setting $22=1 in the Machine Inspector Console Window.

I would always recommend that people enable Homing if their machine has Homing limit switches installed.

{:0)

Brandon R. Parker

1 Like
8

Thank you for the patient explanation Brandon. Had homing been setup all this could be avoided. Will setup then test it out.

1 Like