Practical Pointers for the Maintenance of Grain Moisture Meters
Thursday 19th September 2013
Grain Moisture Meter and Probe Maintenance
Routine maintenance is important for good practice and to comply with farm assurance protocols.
Return to the manufacturer for a full service
Attend a moisture meter clinic
Test against a buyer's sample
Getting the Best out of your Moisture Meter
- Select correct calibration for crop to be tested.
- Keep measuring cell clean and free from contamination.
- Always allow a safety margin, as errors are frequently ±0.5% and much more in very wet, very dry or freshly harvested grain.
- Assess your meter function over a period:
- Do results change after harvest?
- Does it read high or low with very wet grain?
- How do results with your meter compare with those on the same samples sent to merchant(s)?
- If errors consistently occur, have your meter checked. If in doubt, or errors are large, return meter to the manufacturer.
- For trading without penalties allow a margin of safety.
Remember, crop moisture measurement is not an exact science.
When checking a moisture meter/probe it is important to:
- Test samples before harvest if possible to confirm meter function.
- Only use samples from a TASCC-approved or UKAS accredited laboratory.
- Check against several samples covering at the very least 14%to 16% moisture.
- Ideally take meter to location where samples were prepared.
On-farm adjustments are not recommended. DIY adjustments usually increase errors.
To minimise errors a well mixed, representative sample should be taken. Care should be taken to avoid contaminants, e.g. soil or screenings.
The Effect of Temperature
Allow meter and grain sample to achieve the same temperature – usually a few minutes. This is particularly important when meter is stored in a cooler/warmer environment than the grain.
Allow a longer equilibrium period when using a probe in grain recently placed in store.
Loading Capacitance Meters
Use loading devices supplied. It is very important to fill meters with the specified quantities of grain and to keep the meters level.
Grinding Samples for Resistance Meters
Clean and lubricate compressor plunger threads daily. Check the grinder regularly for wear. If a specific grinder is not supplied with the meter, crack grains into two or three pieces. Acceptable results can be achieved with a coffee grinder, but avoid grinding too finely as moisture may be reduced.