TEVO Tarantula Z travel

I recently assembled a TEVO Tarantula and I'm in the process of setting up the auto bed levelling. I issued a G28 and the X and Y home ok. The extruder then was heading down without any sign of stopping when I turned it off at the socket, just before it hit the bed.
What should I check in my settings? And how should I set a safe level for Z.
I have the bed levelling probe fitted.
[i1372.photobucket.com]

Did you test the probe manually? Send M119 to get the status of the endstops. It should read open when in free air and triggered when close to the bed ( or any other object )
If it works, you should mount the probe further down. There are long holes to adjust probe height.
There also is a difference in firmware between Z-endstop and Z-probe.

Quote
o_lampe
Did you test the probe manually? Send M119 to get the status of the endstops. It should read open when in free air and triggered when close to the bed ( or any other object )
If it works, you should mount the probe further down. There are long holes to adjust probe height.
There also is a difference in firmware between Z-endstop and Z-probe.

It says "open" for all 3

Does your TEVO Tarantula has both Z-axis mechanical endstop and auto-bed-leveling Z-Probe?

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Proud owner and maker of build from scratch FDM 3D printer [forums.reprap.org]

Quote
Rossos
Does your TEVO Tarantula has both Z-axis mechanical endstop and auto-bed-leveling Z-Probe?

No, just the probe. The probe is connected to the board in the place where the endstop is normally connected.

I did not have the chance to play with the Z-probe sensor your printer uses, but it seems alot of folks are disappointed in that sensor.
Alot of mentions about it not triggering at 2mm as stated in user's manual. For some it doesn't even want to work with 5V.
There seems a to be a nice long discussion about that particular problematic sensor on Thingiverse' forums here: [makerware.thingiverse.com]
Have a look, maybe it can help you troubleshoot.

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Proud owner and maker of build from scratch FDM 3D printer [forums.reprap.org]

Thanks, that was a useful discussion.
I might try a regular endstop for the time being.
But I have another problem. If I try to move my Z down in Repetier host, it stops about 30mm from the bed and will not go lower.
If I try to home Z, it will then go down - but too far.
Why would it not allow me to move down further in Z?

On my printer, Marlin 1.1.x firmware with OctoPrint 1.3.6 for control, when I power it up it only allows me to move towards positive directions.
It is my believe that it assumes on startup that it's on coordinates X0, Y0, Z0. Because if I issue G28 it does go into negative directions until it hits the endstops.

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Proud owner and maker of build from scratch FDM 3D printer [forums.reprap.org]

I think the problem was that I had loaded new firmware, and "auto bed leveling" had not been enabled in this version.