Rock Hit Detection: when the tile line lifts by itself

A tile plow sometimes meets something it can't go through: a rock, hardpan, an old tile, frost or very dense subsoil. The plow rides up above the tile line. If the app kept driving it down, it would fight the obstacle, then run the rest of the line chasing grade.

Rock Hit Detection sees the plow held up and raises the target to where the plow actually is. The run carries on from there.

Before you start

Time: a minute to read; a minute to turn it on or off.

• You're installing tile in Standard or Contour Tiling (Install the tile).
• Full Automation Kit or Guidance Only Kit. With Ditch Assist® Lite it's always off.

When it fires

All of these at once:

• You're in Tiling (Standard or Contour Tiling) and grading is running: you tapped Start.
• The plow is more than 2″ above the target.
• It stays more than 2″ high for 10 GPS readings in a row: about 2 seconds at 5 Hz, about 1 second at 10 Hz. One noisy reading doesn't count; any reading back under 2″ starts the count again.
• At least 5 seconds have passed since the last rock hit.

What you see and hear

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• The target goes up by the amount the plow is above it, up to 24″ per hit. The plow stops fighting the obstacle.
• The lift is added to Nudge, so the rest of the line runs that much shallower until you change it.
• The top bar gains a Design column. The depth guide shows a blue CURRENT line above the yellow FINAL band, and the box under it shows Current Tgt and Final Tgt.
• The lift only ever moves the target up. It never cancels or reverses a nudge you set yourself.
• The lift saves with the job. Resume tomorrow and it's still there.

After the obstacle

1. Keep going until you're past it

   The plow runs at the raised depth over the obstacle.

2. Tap Nudge Down until the nudge reads 0″

   Once you're clear, tap Nudge Down, the lower blue button on the right. Each tap takes off 2″ (the default). Keep tapping until the number above it reads 0″. The plow goes back to the design depth, paced as it comes down.

   If the obstacle carries on, for example a long hardpan, leave the lift in. Check the depth is still inside your Min Depth.

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3. Check that stretch by hand

   Tile laid shallower over a rock may be under your minimum cover. Mark the spot and check it by hand.

Turn it off or on

It's on to start with. The switch lives in the app's Settings, in the GRADING section.

1. Tap Settings

   On the Home screen, tap Settings, the fourth button down the right side, with a gear icon.

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2. Scroll down to GRADING

   Slide the settings up with your finger until you reach the box headed GRADING (scrolling).

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3. Tap the Rock Hit Detection switch

   Tap the switch at the right end of the Rock Hit Detection row. Dark green with the knob on the right means on. Pale, with the knob on the left, means off.

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• Works in Standard and Contour Tiling only; no other workflow uses it.
• Ditch Assist Lite: the row is hidden and detection is always off, because you move the plow by hand and the target would move under you.
• Guidance Only Kit: the setting works the same as on the Full Automation Kit. You hold the plow yourself, so if you run it 2″ high for a couple of seconds the target goes up too. Turn it off if you want the target never to move by itself.
• Nudge Sensitivity (in), two rows above it, sets how much each Nudge tap moves the target when you take a lift back off.

When to turn it off

• Soft or stony ground sets it off when there's no real obstacle (the plow bobs above grade and the line keeps creeping up).
• You lift the plow often on a job (lots of crossings) and don't want to keep taking the nudge back off.
• A Guidance Only Kit operator who prefers the target fixed to the design.

Turn it back on for the next job: hitting a rock with it off means the plow keeps trying to reach grade, and the rest of the line chases depth.

If something goes wrong

• The banner fired and the line is too shallow: Rock Hit on the fix page.
• Depth swings in soft ground: Slow or chasing.
• Back to the install: Install the tile.