3dTouch Z min problem

[Quanghoster]

Hi,
I have installed my 3dtouch sensor on an AnyCubic Prusa i3. This uses a TriGorilla board. The sensor is testing ok with using the Z_MAX_PIN for the server - I can raise and drop the pin and tell it to self test using G codes. However, the board is always reading that the Z axis is at Z_MIN. I can unplug the white/black connector and connect a resister from the white wire on the board to +5v and the board reads that the z axis isn't at end stop, but connect the 3dtouch and it's always at z_min again. I manually push up and release the pin and I don't see that change. Can you guide me on how I can resolve please?

Thanks,
Andy.

[Quanghoster]

Hi,
I've done some further investigation. I see that you are using an ATMEL ATiny13A processor within the probe. I've traced the z-min output signal (white wire) back through a 100 ohm resister to pin 7 (PB2) on the processor. I have monitored the voltage output on the white wire and I find it is at 0v regardless of whether the pin is up or down. However, if I cause the sensor to alarm, by holding the sensor pin when raising or lowering, so that the LED is flashing I see a difference. The white lead is then raised by the processor to 5v. So it would appear that the processor IO port is still functional. When I try to run G29 after calibrating the home position, The hot end is moved to the three locations, each time the pin is dropped, very shortly after it is raised and the hot end is raised before moving to the next location. The hot end progressively moves away from the bed and never approaches it. I believe the reason for this is that when it is instructed to drop the sensor pin, the firmware is not raising the z-min output signal on pin 7 of the processor, causing the printer to see Z-MIN active and therefore raising the hot end and moving to the next position. I suspect there is in issue with the firmware on the 3DTouch. Can you please consider my comments and let me know how this can be resolved.

Thanks,
Andy.

[Quanghoster]

Here is the option from 2 G29 commands..

Bed x: 50 y: 50 z: 22.00
Bed x: 125 y: 50 z: 33.99
Bed x: 125 y: 150 z: 45.99
Bed x: 50 y: 150 z: 57.98
Eqn coefficients: a: 0.00 b: 0.24 d: 16.00
planeNormal x: -0.00 y: -0.24 z: 1.00
ok
echo:endstops hit: Z:57.98
Bed x: 50 y: 50 z: 39.18
Bed x: 125 y: 50 z: 51.17
Bed x: 125 y: 150 z: 63.17
Bed x: 50 y: 150 z: 75.16
Eqn coefficients: a: -0.00 b: 0.24 d: 33.18
planeNormal x: 0.00 y: -0.24 z: 1.00
ok
echo:endstops hit: Z:75.16

[Quanghoster]

Thanks to Jessie and your technical support team I've managed to solve the problem.

I needed to change the polarity of the Z Min end stop in Configuration.h
i.e. from
const bool Z_MIN_ENDSTOP_INVERTING = true;

to

const bool Z_MIN_ENDSTOP_INVERTING = false;

This now behaves as expected and I can proceed to calibrate the sensor.

Thanks for your support guys...