A. It all comes down to what you want to do with your moisture meter. Neither system has a distinct advantage over the other, however for continuous checking of larger samples, pre and post drying, the AP 6060 is a quick and simple to use, whole grain, capacitance meter which enables fast throughput and is one of the most accurate on the market. It’s large sample size gives a more representative sample.
The Sinar AgriPro marries the convenience of whole grain testing with a small sample size – ideal for spot checks around the farm & field.
Resistance instruments require less sample, tend to be ‘grinder’ style and are somewhat slower to use. Having said that, our Sinar FarmPro meter quickly measures moisture content, after a simple one step grinding/measuring operation, using only either 9ml or 11ml of sample, and is ideal for field walking prior to cutting.

Q. Which is best, a conventional meter or a Grainspear?

A. That’s an impossible question to answer as they are designed to be used differently. You should choose the one that is best for the situation you have. Many organizations have more than one type to suit different applications.

A spear is more commonly used for on-floor drying and in-bin storage. For use in the drying shed, in-field or for loading-in/out grain a traditional design is preferable. However there are no hard and fast rules about which one should be used where, usage and budget will determine which one you require. Call our sales team to discuss your particular situation.

Q. How do you, the manufacturer, calibrate meters?

A. By this do you mean how do we set the initial calibration for a commodity or how do we calibrate an instrument when it’s back for service or repair?

If it’s the former, then over the last 20 years or so, each harvest we’ve collected samples of all the commodities we measure with our meters and oven tested them. The results of these tests are then used to adjust the programming within the meters to make the results you get more robust with time.

If it’s the latter, then firstly we calibrate the hardware to ensure that the mechanics and the electronics are performing to their specifications. Then we check that the moisture results are within specification against a range of known calibration standards. Finally we put each instrument through a final check procedure with a different set of oven tested, calibration standards to confirm the calibration.

Q. How do I know if my meter is giving correct results?

A. Meters that are regularly calibrated by us should give reliable results. Getting an unexpected claim does not always mean that your meter is wrong but is an indication that something may be wrong. A good way of ensuring that your meter is correct is to purchase known calibration standards from us (part No 1900-6352), or in the case of GrainSpears, one of our Field Test Devices (part No 1900-6280), and check your meter against them regularly throughout the harvest. At the first sign that your meter is incorrect contact the Sinar Technology Service Centre and we will help you solve the problem.
Checking your meter against another meter of different manufacture and unknown accuracy is not recommended as this can give misleading & confusing results.

Q. I have more than one moisture meter of the same model and they give different results – why?

A. There are two possibilities.

i) All the instruments require recalibration.
ii) All instruments have a +/- range of error tolerance, typically between 0.3% - 0.5% depending on model, and the differences you are noticing are could be due to this.

All our instruments have the ability to have MINOR adjustments made to them by the user to remove these differences. Any major adjustments really do require a visit to our workshop to ensure that there isn’t something more fundamentaly wrong with the instrument. A minor adjustment would be up to the range of error tolerance for the individual instrument.

Purchase a known calibration standard from us (part No 1900-6352) and check your meter against them to determine which, if any, require recalibration, or in the case of GrainSpears, one of our Field Test Devices (part No 1900-6280).

Q. Why does my freshly calibrated meter still give the wrong results

A. It depends what is meant by wrong. If you mean the results aren’t what you expect, or they’re different to your merchant, then the possible problem is in the sampling. If you and the merchant take a different number of samples per load, then different results may occur. Bad sampling can result in errors of +/- 0.5% moisture or more. The smaller the number of samples (and sample volume) the greater the possible error.

Q. My meter is checked every year but I still get claims for moisture when I send out grain, why?

A. By ‘checked’ do you mean taken to your grain merchant and/or moisture clinic?

These checks are indicating that at one point in time your meter gave a moisture reading that was within an acceptable limit of the merchants’ meter or a test sample, it doesn’t mean your meter was correctly calibrated. There are many other factors that constitute correct calibration and that can only be determined ACCURATELY by a calibration carried out by a technician with all the correct samples and equipment.

The most common reason for claims however is ineffective sampling. Bad sampling can result in errors of +/- 0.5% moisture or more and, unfortunately some farmers do, on occasions, take risks and send out grain that is marginal with regard to contract limits. Remember, meters and spears have a +/- range of error tolerance and if this is coupled with some sampling error then missing the contract limit isn’t inconceivable.

Q. How do I monitor on-floor drying, or in-bin storage, with a meter?

A. It’s very important to monitor on-floor drying, or in-bin storage, regularly. If you’re using a meter, rather than a Grainspear, samples must be collected and tested using a sampling probe. This will ensure that samples are taken from the commodity at various, pre-determined levels and not just randomly up and down the heap. The horizontal position of each sample should be noted along with the results to ensure that drying is progressing both vertically and horizontally. This process means taking a lot of samples and testing, but it’s essential to ensure correct drying and to detect problems, like blocked ducts or fungus growth, at an early stage. Talk to our sales department for your sampling probe requirements.

Q. How good are GrainSpears?

A. GrainSpears are excellent for getting a rapid indication of moisture and temperature from on-floor drying, or in-bin storage, and their repeatability is very good. When monitoring drying, repeated readings over time will confirm progression. Care should be exercised when using them to predict moisture content of grain being sold, meters are the better choice for that purpose.

Q. How do I check the calibration of my GrainSpear?

A. The best way is to send it back to the Sinar Technology Service Centre where we have all the correct equipment and calibration standards to check and adjust the instrument across it’s entire range of functionality. However, a Field Test device, used regularly during the months the instrument is in use, will provide an early indication should the calibration start to drift.

Q. If I have a GrainSpear, why do I need a conventional meter as well?

A. GrainSpears are very good at obtaining rapid measurements of commodity moisture and temperature of on-floor drying and in-bin storage, which will provide indication of drying progression and/or storage problems. A conventional meter will provide a more accurate measure of commodity moisture content for the purposes of buying & selling and is the one that will be used by your grain merchant. The AP 6060 will also give you a very good guide as to Kg/hl (bushel weight) as well.

Q. Why are the results off the drier different from those using in-bin samples taken a few days later?

A. The moisture in the samples off the drier will not be distributed evenly and also the temperature will not be stable. Allowing the commodity to settle for a few days will even these differences out and thus provide a more consistant reading. To obtain a more accurate reading directly off the drier, spread the sample on a tin tray and allow it to cool to ambient temperature. Although our meters do have in-built temperature compensation if there is a big differential in temperature the compensation system is not as effective, i.e. hot grain out of the drier and a sample cell at ambient temperature.

Q. Why does grain from one harvest seem to give different results to the next?

A. There are two questions here.

i) Is the reading in one year different to a reading in another for the same product?
ii) Is there great variability within samples from one year but not in another?

If the question is i), then growing and harvesting conditions will be different year to year and can affect the readings especially with freshly harvested grains. These differences will usually disappear within a week or two once stored.

If the question is ii), then this usually means that something affected the harvesting, such as lodging, sprouting or a high proportion of green grains. Also other things will affect resistance and capacitance readings, such as soil contamination, screenings or other non-grain material. Also ensure that the correct volume of sample is used for testing, the smaller the volume, the greater the error. If you’re not sure what the volume should be, check the instrument user manual or call the Sinar Technology Service Centre.

Don’t be too eager to get the crop in, make sure it’s fully ripe before harvesting as a lot of technical problems are due to unripe seed within the sample, particularly with Oilseed Rape.

Q. What margin of error should I allow on grain I sell?

A. That depends on how good your sampling regime is, because sampling is often the biggest source of error in moisture measurement. The more samples you do per load the more confident you’ll be about the accuracy. Typically +/- 0.5% would be a sensible margin of error to use.

Q. Why do I get different moisture readings from my GrainSpear at the top of the heap to the bottom?

A. There are two main reasons for this.

i) Grain compaction.
ii) Temperature stability.

If the grain has only just been laid, then the compaction is uneven throughout the depth and will become stable after a few days on the floor or in the bin. You’ll see the readings stabilise as the compaction settles down.

If the grain has been down for some time, then most commonly the GrainSpear hasn’t been inserted into the grain far enough, it really needs to go in for approximately half its length to get an accurate reading.

When the GrainSpear is initially turned on, the first reading it displays is temperature. This is deliberate, as the temperature of the sensor needs to stabilise before a moisture reading is taken. The most common error is for the operator to switch the instrument immediately to moisture before inserting the spear and not allowing the temperature to settle.

Q. Why is my repair bill so big? My instrument isn’t that old surely it shouldn’t have gone wrong?

A. We now have somewhere in the region of 17,000 instruments in the field, of which approximately 2.5% - 3.5% are returned for service/repair each year. That means that we really do have a very reliable range of instruments overall.

To help overcome one off, large repair bills, look at our range of service agreements and find one that suits your needs, they can also include a loan instrument whilst yours is away. Please call our Service Centre to discuss your requirements.

Although your instrument may not be very old, in relative terms, the average age of instruments coming in for repair is 5 years or greater. How many other farm tools go that long without repair?

calibration, we also check other parameters at this time, record all the results for future use and then despatch the instrument to the owner.

Q. Why does it take so long to get my instrument repaired when it goes wrong during the harvest, that’s when I need it most?

A. In any year we receive approximately 400 – 600 instruments for service/repair. The vast majority of those come to us during the harvest period so that over a period of about 2 – 3 months we get anywhere between 200 – 400 instruments. It’s physically not possible to repair all these instruments within a week of receiving them and so turnaround times lengthen.

Much of the work we undertake is due to the lack of maintenance and care of meters and spears. Having paid several hundred pounds for the unit when new, many farmers then proceed to abuse them and do not have them serviced. They use them to the end of the harvest and put them away, without cleaning them, in leaky sheds until next year, fully expecting them to work when they get them out again when the next harvest begins. A check of the unit in about February or March would probably let you know in plenty of time if it’s going to work, or not, when you need it.

Take advantage of our range of service contracts, which can include a loan instrument whilst yours is away, or the reduced cost service offer we run every year. Please call our Service Centre to discuss your requirements.