Weight and/or Test Weight Inaccurate after Calibration

15 Feb 2024


If after calibrating an H2 GrainGage, the weight and/or test weight is slightly out of calibration, follow the outlined steps to identify the cause.  


  1. Ensure the weigh bucket of the GrainGage is in the tracks (Weigh Bucket Out of Tracks)
  2. Clean inside the bucket, around the bucket, and around the load cells of the GrainGage with high pressure compressed air.
  3. Ensure there is nothing putting positive or negative tension on the weigh bucket/load cells (i.e. air hoses, cables, overload protection pins etc). 
  4. Apply negative and positive pressure to the bucket while watching the weight values in Diagnostics. Remove the pressure to ensure the weight returns to zero. Do this serval times to ensure repeatablity. 
  5. Put the HarvestMaster calibration weight in the bucket with the top gate closed and check it to ensure the Load Cell 1 millivolts and Load Cell 2 millivolts move when weight is applied and are stable when static. 
  6. Check to ensure the Load Cell 1 millivolt and Load Cell 2 millivolt move when weight is applied and are stable when static. 
  7. If a problem is identified with one load cell from step 6, try swapping Load Cell 1 with Load Cell 2 at the DSP module to see if the problem follows the load cell or the port on the module. 
  8. Check overload protection pins by applying a maximum weight on both the weigh bucket and test cup. 
  9. Check air pressure to ensure it is between 75-85PSI.  Calibrating with the machine running may improve the accuracy.  
  10. Check to ensure seperator cup is moving up and down freely by turnig off the air to the GrainGage and then manually lifting the cup.  The cup should lift and fall back down with little resistance.  
  11. Check the system "Supply Voltage" is more 12 volts by going to DIAGNOSTICS>>MOISTURE.  Calibrating with the machine running may improve the accuracy.  
  12. Check to ensure "Slope and Motion Compensation" is enabled (YES) by going to SETUP>>*GrainGage Device Name*>>SENSORS>>WEIGHT.
  13. Check the "Q" value, when the combine is running, by going to DIAGNOSTICS>>WEIGHT.  The "Q" value should be 1.000 + .1 with combine running. Running a new "Slope & Motion Calibration" will set the "Q" value to 1.000.  

If you are still having issues, please contact one of our HarvestMaster Field Service Engineers