Hello,

I am using Mach 3 with a UC100 connected to a Chinese 6040T CNC router.

Everything has been running fine until this afternoon. The machine was in the middle of a lengthy beveling operation and I went to eat some lunch. When I returned the X and Y were moving along fine but the Z was a couple of inches above the work piece even though Mach 3 was showing that it should be 4mm below the work surface zero.

I stopped the cut to see if I could rezero the Z and backup to the last tool change and start over. Unfortunately, pressing the keys to control the Z resulted in random action. The Z always moves, but whether it is moving up or down is random.

I reset the computer as well as the control box and I double checked the Z configuration in Mach 3, but the issue persists.

Does anyone have any idea how I might determine what the issue is?