I just installed a BLTouch Smart on my i3 2020. I also have the Titan Aero extruder with a mount that sets the BLTouch about 45 mm to the LEFT of the extruder (which according to Marlin means I enter that offset as a negative number.)
I am using Marlin 1.1.5, and can't seem to get the BLTouch to work at all. I followed the directions on the RepRap forums and well as the BLTouch site for wiring it to the Ramps 1.4 board that comes with the i3 2020. The only thing I get is a blue light on the BLT. No commands work. It won't go into test mode, it won't retract or deploy...nada.
As I said, I have the E3D Aero on a mount that sets the point of the BLT 45mm to the left of the nozzle. According to Marlin (1.1.5) I should use -45 for my offset, but when I do it gives me a compile error:
static assertion failed: RIGHT_PROBE_BED_POSITION can't be reached by the Z probe.
Well, after looking at WHY that error triggers I did the math. My bed width is 200, my probe offset is -45, my RIGHT_PROBE_BED_POSITION is set to 190.
200 + (-45) = 155
which is less than 190. This error triggers if the RIGHT_PROBE_BED_POSITION is less than or equal to the MAX_PROBE_X position (which is calculated above). Unless I'm missing something, that math is correct.
If I set the probe offset to POSITIVE 45, everything compiles, but of course the nozzle just smashes into the bed and I have to turn it off because the probe never fires.
I have it wired up according the the BLTouch webpage regarding Ramps 1.4 wiring:
Do I still need the mechanical Z endstop?
I checked all of the wires from the BLT to the board with a meter and I am getting continuity.
Thank you (and help!)