05.06.2025

gedm-support@proton.me

>>> Controlpanel EVOIII is available here <<<

• Updates
  • Update via SD card and creating the initial directory tree had issues - fixed
  • Homing was bricked - fixed
  • Steps per mm setting for the wire feeder stepper
  • Buttons to move the wire back and forward manually
  • Wire feeder stepper is now controlled via mm/min instead of RPM
  • NVS storage resets automatically after a firmware update via SD card

• Bugs fixed
  • Last update missed to update the main.cpp file that had also changes - fixed (06.05.2025)
  • Major bug fix: A mistake created an integer division that resultet in sudden direction changes. Very bad. Fixed (25.05.2025).
  • changing steps per mm via ui was bricked - fixed (5.3.2025)

+ 1. Validate homing routines, XYZ and all with Z enabled and disabled (z not tested but it should work)
+ 2. Validate probing routines (right front edge confirmed working. Other egdes not tested. Should work)
+ 3. Validate sinker mode with and without retractions (Y positive, Y negative, X negative tested with and without flushing interval)
- 4. Validate reamer mode
+ 5. Validate 2d wire mode ( did some cuts. Seems to work)

Firmware for wire and sinker EDM machines build with the G-EDM EVO electronics.

It supports router type CNC machines with three axis plus a spindle stepper. Rotary axis support is planned for the future.

For 2D wire EDM a z axis is not needed. 

Download the repo and extract the folder. Load the folder into visual studio code.
Make sure the platform.io extension is installed in vstudio. After the folder is loaded it will prepare everything.
This can take some time. Once finished restart vcode. If you already have a running G-EDM firmware on the ESP you can
update it by placing the compiled binary on the SD card and just insert it. The initial version will require a restart of the ESP
to start the update. Once the Phantom release is installed a restart is not required anymore for update over SD. 

To use update via SD card press the compile button. The firmware.bin file should be located in the project folder at /.pio/build/esp32dev/firmware.bin Just copy the firmware.bin file into the top root directory of the SD card.

If this is the initial install on a fresh ESP without any G-EDM firmware it needs to be flashed from vcode. Just press the upload button while the board is connected via USB. On windows it may be needed to install the USB to UART drivers first: https://www.silabs.com/developer-tools/usb-to-uart-bridge-vcp-drivers

Some people expierenced problems with inverted colors on the display and it seems that this is related to cheap ESP32 boards or cheap ILI displays. Mostly it is a bad ESP32 board. So don't cheap out on that and go for the AZdelivery stuff.

Also the router used needs a very high step resolution. 3200 steps per mm seems to work. My router version has around 4000 steps per mm. This is important. The spark gap is tiny and a single step should create a smaller travel then the spark gap. We are talking microns here.

After the machine receives an update it is good to factory reset everything. Insert an SD card and open the SD menu. Press the last tab and touch the factory reset button. This deletes the NVS key value store used to store the settings from the last session.

A factory reset after the initial installation is required. After flashing the firmware on a fresh ESP32 perform a factory reset to write the default params to the NVS storage. If the XYZ positions show as -1 this is due an empty NVS storage.

The new code has a different configuration for the voltage feedback (vFd) short circuit threshold. The new default vFd should be almost 4000 @ the max possible voltage. Set the DPM/DPH to the max voltage. if the DPH is used with the 0-80V PSU something around 80V is the max possible. With the DPM it is 60V. Then turn the motionswitch to OFF and press the start button on the display. This will enable the scope. Ensure that the DPM/DPH is also turned on and adjust the Poti on the pulseboard until the reading below "vFd" shows almost 4000. It should never go above 4000.
It is very important to have the vFd set to a low voltage feedback before ever connecting the JST bridge to the sensorcircuit!

Once the vFd feedback is set it should look like this on the scope with the maximum input voltage turned on. To activate the scope turn the motionswitch to OFF, enable the DPM/DPH with the max voltage (max 85v), press the start button on the display. Now the scope is active and PWM enabled too but with the motionswitch OFF it will not start any process. Almost 4000 but no spikes above 4000 at the vFd reading. If the value is >4000 or worse stuck at 4095 turn everything off, buy two pizzas and contact the emergency hotline.

1. Machine doesn't move but everything looks good

   If the process starts but the machine does not move at all it is mostly related to a wrong vFd setting. The pulseboard provides the voltage Feedback (vFd) in an inverted way: No load / no voltage drop provides a high reading. If the current exceeds the settings on the DPM/DPH the voltage starts to drop (the goal is to avoid voltage drops and consider every voltage drop a short circuit). Increasing the current on the DPM will make the voltage drop later while lower current settings will result in a faster voltage drop. In the settings menu is one parameter called vDrop Threshold. If the vFd value shown on the scope drops below this value it is considered a hard short circuit. If this value is larger then the vFd value without load the machine will not move. This threshold should be around 200-300 lower then the vFd value without load. Noise in the signal should not make vFd drop below this value. 200 difference is normally save. There are different thresholds for probing in the menu. probing uses a smaller voltage and therefore the generated vFd is lower then at full voltage.

2. What are the most important paramaters?

   Setpoint MIN: The higher this value is the more aggressive it will move forward

   Setpoint MAX: This one is almost not needed anymore. The average peaks shown on the scope should not be higher then that. Can be set high enough to not be triggered at all. As said it is not needed anymore but may trigger some savety stuff if too low.

   PWM Duty: A higher duty will generate a more powerfull discharge and thus drop the voltage faster. The duty needs to be high enough to create a sharp voltage drop on short circuits!

   Current on the DPM/DPH: Start with 0.4A to get a fast drop. Increase to 0.8A and once everything runs good try 1A.

   Zeros in a row: Defines the number of empty readings before the machine is allowed to move on. Higher values will make the process progress more sensitive and save.

3. What frequencies to use?

   Currently it is best to stick with the 20khz. Using different frequencies requires knowledge about how the software works. It is not as easy as just changing the frequency. The ESP32 does not allow synchronous ADC readings triggered by the Pulseoutput. Therefore it is required to sample in continous mode and filter the results. The lower the frequency the larger the OFF time and the empty readings wich needs to be adresses by adjusting some in depth paramaters. I am working on it to make it easier.

4. Motionplan timeout

   Have seen this error with a default DPM/DPH. By default those devices are set to 9600 baud. The communication on the ESP operates at 115200. The baudrate of the DPM/DPH needs to be set to 115200. Press the set button until the menu opens and navigate to the entry "6-bd". Adjust this value to 115,2 and confirm with ok. Now the communication should work. Open the settings page and navigate to the DPM settings. Enable DPM communication. By default it is disabled. It should now show the voltage and current. If it shows -1 values there is something wrong.

1: If the screen is touched on bootup it will enforce a display recalibration. Once the display turns black it can be untouched and the calibration will start

2: If for some reason the display blanks out in the process it is possible to re-init the display by touching any point on the display that is not a touch element. In the process only two elements are touchable. Settings button and pause button. Touching the area above those buttons will re-init the display (don't know if it works in the case of a bricked screen) Works only if the settingsmenu is not open.

This is up to you as long as the machine is a router (no moving table) Support for moving tables will follow but the code started to get complex and therefore I focused on routers and skipped support for mills.

The Motionboard runs with 4 TMC2209 drivers and I use big Nema17 steppers with 1.67A. A few people removed the TMC drivers and used the raw step/dir signals to run external drivers with Nema23 motors. It is possible too.

I highly recommend to take a look at the work from Alex Treseder for an easy to build wire EDM machine:

https://github.com/alextreseder/picoEDM

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Lautensack Roland (Germany)

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