Near Intersection of I-35 & I-90 Southern Mn. | Ah yes, Three Dog Night - Partied to that song many times.
The calibration issue can be a bit confusing at first but this is part of the reason that the Ag Leader monitors can be very accurate. Some other brands are easier in this respect but don't produce as accurate results.
The C1-C11 numbers are important calibration numbers. C1 is the vibration number. The purpose of C1 is to remove any flow indications that are due to the vibrations generated by the combine/head without grain flow. This value varies from combine to combine and is dependent on the combine's design and indvidual characteristics.
C2-C11 are the calibration numbers for the various flow rates for each grain type. The Ag Leader system splits the capacity of your combine into 10 categories. Each category has a value for each grain type.
The system basically decides which category the flow rate is in at any given time and records this. This is how the flow against the sensor in the clean grain elevator is converted to wet weight which eventually gets converted to dry weight, bushels and finally yield.
To get started with a virgin system, the C11 number can be entered based on the value suggested in the owner's sheet for a specific model of combine and grain type. This is Ag Leader's best guess for these values for your combine. These values should be reasonably close since they have tested all the various combines.
When you enter in C11 for your combine. the C2-C10 numbers are created based on this value. If you made a graph of the C2-C11 numbers and joined the dots you would find that this graph is a straight line or a linear relationship. This is a good starting point.
When you do an actual calibration you are entering in history so that the system can fine tune these numbers based on what is actually happening with your combine. This is why it is important to do smaller cal loads where in the flow is consistent within each load. You are advised to do several cal loads where the flow is different between cal loads but consistent within each load.
It would seem that doing a larger cal load should be better but this is not really the case because it is usually difficult to maintain a consistent flow rate within a larger load.
After you enter the actual weights and allow the system to fine tune itself, it will change the various C2-C11 numbers somewhat in an attempt to get the values in agreement with your weights. If you made a graph of the revised C2-C11 numbers you will find that the graph is usually no longer a straight line but has a curve to it. This should be a more accurate reflection of your combine for each grain type.
Because the flow and chracteristics of each grain type are different, there is a set of C2-C11 numbers for each grain type.
The Ag Leader system bases the weights, yields etc on these C2-C11 numbers and records the "hits" in each category rather than the computed weights etc. This means that if the C2-C11 numbers for a grain type are changed, the values (weight, yield etc.) for previously harvested fields will change slightly.
In other words, suppose you start harvesting corn with the original C2-C11 numbers and observe the yield. If you later perform a calibration which changes the C2-C11 numbers and went back and reviewed the results for the first field you might find that they have changed somewhat. Generally this is desirable but there are a few cases where this is undesirable.
We have some growers who raise "waxy" corn and regular corn. To get really accurate results some of these folks actually have two types of corn defined - waxy and regular within their monitors. Each type of corn has its own unique C2-C11 numbers.
Part of the calbration issue depends on your goals. If you goal is to get a relative feeling for how one variety compares to another or how one fertilizer treatement compares to another then absolute accuracy is maybe not that important since you are interested in relative accuracy. In other cases absolute accuracy may be more important.
After you've worked with this awhile you will appreciate how difficult a task yield monitoring really is. It is far more complex than getting a sprayer to apply the correct amount of chemical.
If your Arrow always points North but does move about the screen correctly then it is quite likely that you don't have the VTG message turned on in the GPS receiver. The GPS settings should be 4800, 8, N, 1 with GGA and VTG ON and all other messages OFF. I have seen this on my own personal PF3000 several years ago. I will confirm this on my GPS simulator today but I'm quite certain this is the problem.
Edited by tedbear 8/28/2009 07:17
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Most used word in the manual......!
