I have the probe working perfectly without a Z Endstop on my Cartesian Printer using Delta Grid Auto Levelling.
I have Wiring Configured similar to the most recent diagram from BLTouch but i DO NOT have a resistor wired in and it works perfectly. Mine is wired as:
Probe Z Min Signal & Ground - Z Min Endstop Signal & Ground on the board.
Probe 5 Volt Supply - Z Min Endstop 5 Volt Supply on the board.
Probe Servo Signal - Any PWM Capable Pin - Needs to be defined in the config file, (In my case P1.23 (MKS SBase)).
Probe Ground - Grnd Next to P1.23 (Any Grnd).
The Servo Settings in the config file are as follows:
##BLTouch Servo Settings
switch.servo.input_on_command M280 S3.0 # M280 S7.5 Would be midway
switch.servo.input_off_command M280 S7.0 # Same as M280 S0 0% duty cycle, effectivley off
switch.servo.output_pin 1.23 # Must be a PWM capable pin
switch.servo.output_type hwpwm # H/W PWM output settable
switch.servo.pwm_period_ms 20 # Set Period to 20ms (50Hz) - Default is 50Hz
Gamma Min endstop is defined as nc.
The rest of the setup is done in the Pre-Print GCode, in Pseudo terms the process is:
- Raise Z 10mm
- Home X & Y
- Move Toolhead to the bed centre
- Deploy Probe Pin
- G31 to probe the bed and turn on compensation
- Return to the centre of the bed
- G30 Znn - Here is where the Z Probe offset is defined.
- Retract Probe.
In GCode it looks like this:
G28 X Y
G1 X0 Y0
G1 X0 Y0
G30 Z2.2 (My Z Probe Offset is 2.2mm)
If i have missed some details you need just ask, but this is working very well for me.