Probing

Touching off by hand puts the datum wherever your eye and the paper strip agree. A probe finds the same feature the same way every time, and writes the answer straight into the offset.

The PROBE screen holds three kinds of cycle:

Group	Finds	Writes
Part zero	where the part is	the active work offset
Tool	how long the tool is, and whether it is still there	the tool table
Calibration	what the probe itself is	the probe’s own numbers

Each cycle is a single step. You position the probe, press the cycle, and the number is set. There is no separate apply.

Arm the probe first

Nothing measures until the probe is activated with ACTIVATE on the screen. It stays armed until DEACTIVATE, and it is dropped on a reset or an emergency stop, so it is never left armed after an interruption.

Two settings every work-probing cycle needs

Setting	Is
the probe’s tool number	which tool position the probe occupies
the probe feed	one feed for every work-probing cycle, not per cycle

The feed is deliberately shared. The effective stylus radius is only valid at the feed it was calibrated at, and every cycle spends that radius. A per-cycle feed would have been a per-cycle measuring error with nothing on screen to show it.

Calibrate before you trust anything

An edge is not where the probe triggered. It is the trigger point plus the stylus radius, in the direction of travel, and the control reads that radius from the probe tool’s R.Geom entry in the tool table.

An uncalibrated probe has a radius of zero. Every edge it finds will be out by exactly the stylus radius, confidently and consistently. Calibration comes first, and again whenever the stylus is changed.

After a touch

The probe returns to the position you handed it, in machine coordinates. That position is known to be clear, because it is where you put the probe, which is why returning to it is safe.

What probing does not do

• It does not check the part is the right size. An edge has no nominal to compare against. These cycles report where a feature is, not whether it is correct.
• It does not protect the approach. Getting the probe near the feature is yours; G31 P11 exists for the part of that you do not trust.

Where to go next

• Part Zero with a Probe, the everyday ones.
• Calibration. Do this first.
• Probing from a Program: G31 and the result record.