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What You Need To Know About Loss Monitors

As the sophistication of farm equipment moves ahead in leaps and bounds, there is hardly a cab on any new machine that doesn’t have an electronic screen to monitor a variety of functions. The range of features those systems include grows every year, and farm equipment operators now put a lot of faith in the accuracy of information they see on display screens.

But when it comes to grain loss monitors, things are a little different. The data on the screen won’t paint a very clear picture of what’s going on behind the combine unless you’ve taken the time to properly adjust it. And you also need to learn how to properly interpret the information it provides. The only way to do that is to get down on your hands and knees behind the combine and see for yourself exactly how much grain going out the back, then relate those findings to the monitor’s readings.

“Grain loss monitors in combines, when properly used, can be one of the best tools to help an individual understand how well his combine is performing,” says Kelly Kravig, platform marketing manager for Case IH combines and headers. “However, when improperly used they can be misleading and actually work against a guy.”

Les Hill, manager of business development and technical services at PAMI (Prairie Agricultural Machinery Institute) agrees. He says while loss monitor systems may now use better electronics than those installed a decade or two ago, they still rely on the same basic principle they always have to provide data to the operator. And he’s seen farmers put a lot of faith in loss monitors without really understanding what they do and how they work. “We put a lot of confidence in electronics,” he says. In an uncalibrated monitor, though, that faith can be misplaced.


To understand why, you first know how a loss monitor works.

“From a technical standpoint the systems are fairly straightforward and fairly simple,” says Kravig. “The loss mechanisms are typically little square or oblong plates that are sensitive to grain hitting them. When a kernel hits those plates it sends a ‘ping’. They measure the number of hits or contacts. Then they send a signal back up to the cab.” The in-cab monitor interprets those pings and provides a readout for the operator, usually as a graph.

Sensor plates are mounted in locations that allow them to sample losses from three key systems: the rotor, sieve, and tailings. Usually, sensors doesn’t require any type of routine maintenance. But over time some crops, such as milo, can leave a residue on them that decreases their sensitivity. “Occasionally, if you get into a certain crop with sap or sticky material it can coat the sensors,” says Kravig. Simply cleaning them will solve the problem.

Testing the system once a year to make sure it’s working is adequate, says Kravig. He says that is best done by having someone tap lightly on the sensors with a pencil while watching the in-cab monitor to ensure there is a good strong signal. “We very seldom find any issues with the sensors,” he says.


Knowing the system is operating correctly is only the first step. The operator then needs to set the sensitivity correctly. “One of the biggest challenges we run into is guys don’t take the time to adjust the sensitivity or take the time to adjust it for the different crop sizes. If you can imagine how big an impact a canola seed would have on that plate, and then at the other end of the spectrum how big an impact a kernel of corn would have. If you haven’t taken the time to set the sensors for the crop your in, you’re driving blind.”

He says once loss monitors are adjusted for the type of crop being harvested, that setting should not need to be altered, unless changing to a field with a significantly different variety.

“But just as importantly, we encourage customers, especially when they get into a crop for the first time in a season, to set the machine and get an acceptable sample in the tank. Then they need to do some loss checks behind the combine. In other words stop the machine, get out, look at the machine and how well it’s performing and do some seed counts (on the ground). Is your loss behind the machine acceptable?”

“Unless you calibrate it, all it is, is a (meaningless) electrical signal,” says Hill. He explains there is no way to understand the monitor’s readout without getting on your hands and knees and physically checking what is really going out the back. “You don’t know if it (the signal) was really grain or not; you don’t know if was a representative sample or not; and, you have no relationship between the number of strikes (and the actual number of kernels lost).”

Making that inspection on the ground behind the combine means you need to temporarily remove the chopper, if your combine has one. It’s impossible to get an accurate count of seeds on the ground when they’ve been scattered across the width of the header. (See the sidebar for more information on how to calculate bushels- per-acre grain losses.)

Hill adds operators need to be cautious of using a monitor to make combine adjustments on the go. “(Without physically checking) you still don’t know what happened. If you adjusted the wind (for example), did you just move the material to a different spot or did you blow it over (the sensors)?”

Once you have the combine set properly and established the real grain losses behind it are within a tolerable range, you need to set the monitor’s threshold numbers to reflect that. “Once you adjust the machine to an acceptable (loss) level for the crop you’re in, then you need to recalibrate your loss monitor,” says Krevig. “Then as you operate through the field and the loss goes up on the sensors, you know you need to slow down or adjust for changing conditions. The guys that do that well put more grain in the tank and more money in their pocket.”


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About the author


Scott Garvey

Scott Garvey is a freelance writer and video producer. He is also the former machinery editor at Grainews.



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