Thread: Limit switch help on a BP retrofit

I'm doing a retrofit on a BP Series 1 CNC, and need help with the Z axis limit switches. I'm planning to use Mach 3 on a PC.

The BP originally had 3 limit switches on the Z axis, top and bottom as usual, but the third one is a "deceleration switch". It is used to slow the travel before hitting the top limit, apparently if it's going too fast something bad happens.

Can anyone suggest how to utilize this switch, or handle the function some other way?

Typ use as home. Then the other two can be wired as hard limits to the drives.

Originally Posted by jrlandau

The BP originally had 3 limit switches on the Z axis, top and bottom as usual, but the third one is a "deceleration switch". It is used to slow the travel before hitting the top limit, apparently if it's going too fast something bad happens.

The outside pair are hard limits.
The inside one is used when referencing the machine and tells the control to look for the index pulse from the encoder.

I used that switch for home. The other 2 are estop as mentioned