Z axis travel/ Program exceeds machine maximum on axis Z

Perhaps I figured it out. If I hit touch off and enter 1" z height then the machine drops to 1 inch and starts running through the cuts. This is great!

Then if I reset home to be 0,0,0 restart and touch off to 1" I again get the same error that my z exceeds the negative limit.

How is the z typically set up and what is the typical home position?

Bearfood wrote: Perhaps I figured it out. If I hit touch off and enter 1" z height then the machine drops to 1 inch and starts running through the cuts. This is great!

Then if I reset home to be 0,0,0 restart and touch off to 1" I again get the same error that my z exceeds the negative limit.

How is the z typically set up and what is the typical home position?

According to your hal file Z is showing that you have two joints BUT you only have one joint for Z in the ini file.!!

How are you homing. It seems you don't have home switches. If this is a gantry machine it would be good to have home switches so that you can auto square the gantry.

The Z is normally home at the top with Z- going down.

More info on the machine wound help

It's a lowrider2 if that helps. www.v1engineering.com/lowrider-cnc/

I have not set up limit switches yet mostly because I haven't figured out how to mount them. They're on my list of things to figure out and do.

The machine is 48"X, single motor on GT2 10mm belt. Y is 48" dual motor on gt2 10mm belts and z is 5" dual motor driving lead screws.

Controller is a Mesa 7i96 attached to TB6600's for each of the joints.

I'll reset home to be at 5" for the z axis for now.

It generally works best to have the top of travel for the Z axis as zero (in machine coordinates) and then have the bottom of travel a negative number.

So, Z axis max limit is zero, and minimum limit is negative.

Apart from any other reasons, lots of CAM packages like to put an absolute move to Z=0 at the start of the G-code. This is bad if z=0 is under the top of the table.

Thanks. So I've put home for z as 5 inches in the air and allowed -5 travel. I know I need to set limit switches but how do I set home without for now? When I start Linuxcnc I have to home all the joints but I can't seem to move them prior to homing them.

Once I get the limit switches set up how do I execute an auto home?

This has been pointed out more than once already:
You have these lines in your HAL, setting parameters to values that are supposedly in your INI [JOINT_4] section

Yet in your INI there is no [JOINT_4] section at all. So I my opinion this config should not even load but fail with an error message.

Are you sure you posted the correct files?

[edit]
This hal and ini file combination would fail to load and give an error:
"INI variable [JOINT_4]P not found"
So these cannot be the correct files.