The combine grain yield monitor is a device coupled with other sensors to calculate and record the crop yield or grain yield as a modern-day combine harvester operates. Yield monitors are a part of the precision agriculture products available to producers today that provide producers with the tools to reduce costs, increase yields, and increase efficiency. The present day grain yield monitor is designed to measure the harvested grain mass flow, moisture content, and speed to determine total grain harvested. In most cases today this is coupled with global positioning system to record yield and other spatially variable information across a field. This allows for the creation of a grain yield map which provides information on spatial variability and supports management decisions for producers. The grain mass flow sensor must be calibrated to provide an accurate estimation of grain flow from the electrical signal produced by the load cell. Different models of the grain mass flow sensor use different methods of calibration, with some being as simple as a linear single point calibration. Improvements in this area have resulted in the use of multi-point calibration to provide a more accurate characterization of the load cell response.The calibration process entails harvesting consistent crop at a constant speed to produce a consistent grain mass flow rate to the mass flow sensor. A calibration is started through the yield monitor installed on the harvester and the operator begins harvesting grain. Once the recommended amount of grain harvested per the manufacturer's recommendations has been harvested, the grain is offloaded into a grain holding device equipped with an accurate scale to measure the actual weight of the grain harvested. This grain weight is then entered back into the yield monitor and is used to adjust the calibration that relates the electrical signal of the load cell to grain mass flow. Several factors affect the accuracy of the calibration beyond the calibration itself. Build up of material on the impact plate can cause the load cell response to be dampened to impacting grain, reducing the load cell response. Wear on the impact plate can also cause reduction in accuracy of a calibration. The chain tension of the clean grain elevator affects the velocity at which grain is expelled from the elevator which changes the force that is applied at the impact plate. Manufacturers often advise properly tensioning the clean grain elevator before calibrating the grain yield monitor