Axbb-E. With UCCNC probe issue

[Mathieu 33]

Hello,

I have an issue with probe ( simple probe mode) with the only Z axis.
On diag mode, the probe works. I use simple sheet metal 5 mm thick and two cables + and -.

When I click «  probe » the Z move up one time 2mm and quickly After few mm. The same result when he detect metal during probe I think.
But the Z axis never go down for detect the plate . Something looks revered somewhere But I don’t know.
Even if I set a minus value in axis 1 P1…

Strange