Slope sensor’s quick response to pitch speeds tile drainage

HARWOOD, N.D. — Tile draining a quarter section, only to find it doesn’t work as expected, is a heartbreaking and budget busting experience.

A ballpark figure for tile drain on the Prairies is $400 to $600 per acre. With the pipe buried one to two metres below the surface, digging and correcting thousands of metres of mislaid pipe is an expensive and daunting task.

“Do it right the first time,” is the main advice experienced custom tilers have for producers thinking about subsurface drainage.

Tile installation is all about economics and time. The fall tillage window is a small one. When Mother Nature slams the window shut, it means the tile plow is going to sit idle for the next nine months.

Running the tile plow faster allows custom operators and farmers to tile more acres and make better use of the investment, said Perry Rust of Rust Sales Inc. at Harwood, North Dakota.

That’s why his company set out to develop better tile plow hardware to work with AGPS Pipe FM and Pipe Pro software.

The DAC 7000, which was introduced in 2010, is a multi-control module that manages functions of a tile plow.

The DAC 2X Slope Sensor, introduced this year, controls the long-slope pitch of the in-ground working tool as well as compensating for cross-slope or lateral roll of the plow.

“Last year, I was putting down tile with the DAC 7000 but without a slope sensor. We could run one to 1.5 m.p.h.,” said Rust.

“This year, we have the 2X Slope Sensor and we’re putting down tile at 2.5 to three m.p.h. I have run four m.p.h., but the stringer crew has trouble keeping up at three m.p.h. With the control module and the slope sensor, we’ve increased ground speed by 1.5 m.p.h. without sacrificing accuracy. That’s big in this business.”

Rust said the two sets of hardware working in conjunction with one another allow him to nearly double his efficiency and the number of acres he can tile in a year. That’s good news for custom operators and farmers who always want the widest possible fall window.

“Yesterday, (Oct. 24) we put down 17.5 miles of tile all in daylight hours. The profile view on the monitor was either perfect or 1/100th of a foot off in 100 feet.”

Rust said he can’t expect that kind of high performance on a regular basis, but it does show how efficient a tile plow can be with the right control systems. The next step in the quest for efficiency is to design a better stringer trailer so crews can keep up with the plows.

The DAC 7000 is a multi-control module running the hydraulic valves that position the plow in the soil. It has digital, analog and CAN compatibility, thus the DAC designation.

Rust said he was forced to develop his own control systems because the third party controllers he had been using didn’t do the job he expected.

The DAC 7000 can interface directly with a tractor’s selective control valve or plug directly into its existing external valves. It interfaces with John Deere, Challenger and Case-New Holland, controls all plow functions and provides roll information to compensate for side hills.

“Pitch is important on a tile plow,” Rust said. “It’s basically the same as getting the sweep pitch right on a cultivator. If blade set is wrong, your results are wrong.”

Rust Sales is a dealer for the Waynes Plow. Like most modern tile plows, it has double links to determine pitch.

“But it’s a little hard to control sometimes with all those links. RTK does a good job of controlling elevation or depth, but it’s far too slow to control pitch,” he said.

“A plow in the soil is a lot like an airplane in the sky. You must always have precise control of the pitch. No time delays. The plow in the soil behaves like the elevator on an airplane. Until now, ground speed with a tile plow has been limited to 1.5 m.p.h. because RTK is too slow to manage pitch.”

He said low ground speed with an expensive tractor and tile plow means the machine owner is not getting the best return on investment.

A pitch sensor that reacts faster allows the rig to run faster, and the economics of owning a tile plow take a turn for the better.

“RTK reacts to elevation change about 10 times per second. That’s far too slow for any kind of improvement in laying pipe,” he said.

“Our 2X Slope Sensor takes readings and gives instructions about 100 times per second. Now, finally, we’re quick enough to manage pitch and roll at a higher ground speed. Here’s a common situation. You’re laying tile and suddenly you hit a hole or a soft spot. It happens far too fast for a human to react or for RTK to react.”

Rust said a farmer will have to come back later with a backhoe to re-install the pipe if the reaction isn’t quick enough at the hydraulic valves. It’s an expensive glitch caused by slow software.

He said the DAC 2X Slope Sensor reacts fast enough to catch these spots and make the adjustments on time, even at four m.p.h.

There’s nothing revolutionary about the 2X Slope Sensor. Most earth altering machines and auto steer systems have some sort of dynamic measuring unit (DMU) or slope sensor to give them better accuracy.

For example, land levelers are now capable of putting lateral instructions together with elevation instructions. They can’t achieve that without a DMU or slope sensor.

“Think about this. If you’re running a land leveler with a slope sensor, you eliminate the need for two GPS systems. The slope sensor does all that math for you.”

The DAC 2X Slope Sensor has other hidden tricks. When used on a tile plow mounted on a rubber wheel tractor, it compensates for tire compression resulting from the down pressure when the plow pulls into the earth.

There’s no track compression on rubber track tractors, but the DAC 2X does the same kind of calculation to compensate for soil compression when the plow is engaged.

“Compaction from the tractor might only be a couple tenths of an inch, but we program it into our software. We deal in tenths of an inch and hundredths of an inch in this business.”

Rust said accounting for those small measurements may seem like overkill to many people, but think about what happens to a tile plow working in regions with genuine elevation changes.

“Imagine a tile plow laying pipe up a slight rise. At the top, the GPS tilts slightly and gives your controller incorrect data, or a side slope sends wrong data. Bad information messes up your whole drainage system.

“We have algorithms in the DAC 2X that account for those situations. We keep the plow at the correct pitch through up-down and side-to-side changes. That’s why we named it 2X. It deals with fore-aft pitch as well as side slope roll factors.”

The DAC 7000 kit has a list price of $1,485, while the DAC 2X Slope Sensor kit lists at $2,250.

For further information, call Rust Sales Inc. at 701-282-9194 or visit

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