Inside this Issue

Page

A Glimpse into the Past ‐ 100

Years Ago 1

A New Generation of Grain

Moisture Meters 2

This Month in History 1

Calendar 2

This Month in 

History

February 1, 2003 ‐ Space Shuttle Columbia

broke apart over Texas as it was preparing

to land killing seven crew members. 

February 3, 1870 ‐ The 15th Amendment to

the U.S. Constitution was ratified, which

guaranteed citizens the right to vote regard‐

less of their race, color, or previous condi‐

tion of servitude.

February 3, 1913 ‐ The 16th Amendment to

the U.S. Constitution was ratified and gave

Congress the authority to collect income

taxes.

February 6, 1788 ‐ Massacusetts became

the 6th state to ratify the U.S. Constitution.

February 6, 1895 ‐ Baseball great, George

Herman “Babe” Ruth (1895‐1948) was born

in Baltimore, Maryland. 

February 8, 1910 ‐ William Boyce founded

the Boy Scouts of America.

February 27, 1950 ‐ The 22nd Amendment to

the U.S. Consitution, limiting the president

to two terms, was ratified.

1

Volume 3 Issue 1

February 6, 2012

A Glimpse into the Past -

100 Years Ago 

By Linda Crown, Editor

What was discussed 100 years ago at the meeting of the Weights and Meas‐

ures Community? In looking at the report from 1912, which was the seventh

Annual Conference, the content of packaged goods were discussed. The

weights and measures community were concerned that consumers be aware

of what and how much they were buying. The following resolution was put

forth by Mr. Joseph (Sealer of Weights and Measures, Richmond, Virginia) to

the meeting attendees with the intent for it to be introduced into Congress.

Resolved, That this body recommend to Members of Congress that

the Congress shall pass a uniform law providing that all foodstuffs,

both fluid and packaged goods, be stamped with the standard weight

and measure on the outside of such package containing such food‐

stuffs, and that all such goods be subject to inspection by the sealers

of weights and measures in their respective jurisdictions, wherever

such goods are manufactured or sold.

Resolved further, That a committee be appointed to present these

resolutions to the Congress of the United States, and that sufficient

copies be published for distribution to each member of this body

among their respective Senators and Representatives in Congress.

Further discussion ensued and Mr. Joseph also stated that “if there is an open

gateway for fraud it is through the package‐goods system in the South.” Mr.

Joseph thought manufacturers should be required to “brand both gallons

and fractional gallons on all bottles, and to brand the weight in ounces upon

all their foodstuffs, so that when they are sold the consumer can regularly

see what they are paying for. I therefore move that this resolution be re‐

ferred to the committee, in order that the subject may be considered.” This

motion was seconded. 

Additional comments were heard from Mr. Emery (State Superintendent of

Weights and Measures, Wisconsin) with a question about which provisions

of the Constitution the request for the resolution would come under – inter‐

state commerce clause or the weights and measures clause. The Secretary

(Mr. L. A. Fischer, Chief of Division of Weights and Measures, National Bureau

of Standards, Washington, D.C.) spoke that he didn’t see why the resolution

should be limited to foodstuffs and suggested it should include all commodi‐

ties. This was backed up by Dr. Reichmann (State Superintendent of Weights
Calendar 2012

Registration for training in the NIST Office of

Weights and Measures is handled by Yvonne

Branden at yvonne.branden@nist.gov.

Course descriptions can be viewed on the Office of

Weights and Measures website by clicking on the

name of the course. 

http://www.nist.gov/pml/wmd/calendar.cfm

February 6 ‐ 10 (1 week)

Fundamentals of Metrology

Class No. 5153

February 15 (2 hours)

Webinar ‐ Traceability Assessments for Weights &

Measures

Class No. 5160

February 27 ‐ March 9 (2 weeks)

Mass Metrology Seminar

Class No. 5165

March 1 ‐ 7

Weights and Measures Week

Contact: info@ncwm.net

March 14 (2 hours)

Webinar ‐ Traceability Assessments for Weights &

Measures

Class No. 5161

March 22 ‐ 23 (2 days)

Measurement Science Conference/9th Interna‐

tional Temperature Symposium

Anaheim, CA

Contact: http://www.msc‐conf.com/

March 26 ‐ 29

SEMAP*

Myrtle Beach, SC

Contact: Robert McGee at

rmcgee@scda.sc.gov

April 5 (2 hours)

Webinar ‐ Traceability Assessments for Weights &

Measures

Class No. 5162

April 19 (2 hours)

Webinar ‐ Conducting an Effective Management

Review

Class No. 5174

April 23 ‐ 27 (1 Week)

Fundamentals of Metrology

Class No. 5163

(continued on page 3)

W&M Connection 2 Volume 3 Issue 1

A New Generation of

Grain Moisture Meters

By G. Diane Lee 

One of the technologies currently used in the commercial determination of

grain moisture is dielectric technology, a technology that has been in use for

over 60 years. Although dielectric technology has some inherent limitations,

meter moisture determination has improved over the years with its use. Re‐

search in recent years by the Agriculture Research Service (ARS) and the

United States Department of Agriculture (USDA) has provided new insight

into the way moisture is sensed by dielectric type grain moisture meters. In

addition to providing a brief history of dielectric technology, this article de‐

scribes research that will give rise to a new generation of dielectric moisture

meters, the impact of this new technology, and the selection of a new official

meter. 

Dielectric Moisture Meters – Pre-1998 Meters

Although some meters were automatic and displayed the results digitally

without calculations, many of the first commercial dielectric grain moisture

meters, including non‐National Type Evaluation Program (NTEP) meters man‐

and Measures, Albany, New York) and he suggested the resolution should be

“very explicit and apply to all commodities. The resolution should not be in

a net‐weight proposition, but a net content of container proposition, or a

net‐quantity proposition; because by making it simply a net‐weight proposi‐

tion you give the opponents of such a proposition the very lever that they

want.”

After additional discussion, it was agreed that a committee of three would

work on the wording and the item would be put in the proper form for sub‐

mission to Congress. Mr. Emery asked, “If this should become a law, what

would be the relation to the State law?” Dr. Reichmann responded, “I think

it would be very foolhardy for us to decide, or even to suggest to Congress,

which side the proposition it would take. We must take the attitude that we

leave it to their superior wisdom.”

It is interesting to see that we are still dealing with the same issues today,

packaging and labeling. This was a major concern in 1912. The weights and

measures representation felt that citizens should know what they were pay‐

ing for. What I found interesting was the faith in Congress to decide this

should become law and to use the power conferred on that body to fix the

standards. Today, we continually work to uphold the standards that were set

in motion with this meeting. While there are those out there who would be‐

lieve that weights and measures is not very interesting, looking back in history

gives you a new perspective and appreciation for the work that has been

done over the years to maintain standards to protect the consumer. And,

the interesting part is seeing the birth of it all through the meeting history of

the Conference on Weights and Measures.

We hope you enjoyed this glimpse of the past. 
May 3 (2 hours)

Weinar ‐ Internal Auditing Best Practices

Class No. 5173

May 7 ‐ 18 (2 weeks)

Mass Metrology Seminar

Class No. 5166 

May 14 ‐ 17

Northeastern Weights & Measures Association

(NEWMA) Annual Meeting

Seekonk, MA

Contact: James Cassidy at

jcassidy@cambridgema.gov

May 20

World Metrology Day

Contact: BIPM at

http://www.bipm.org/en/convention/wmd/

May 21 ‐ 24 (4 days)

WRAP*

Cheyenne, WY

Contact: Rober Weidler at

rweidl@state.wy.us

May 20 ‐ 24

Central Weights and Measures Association

(CWMA)

Cedar Rapids, IA

Contact: Ivan Hankins at 

ivan.hankins@iowaagriculture.gov or

http://www.cwma.net/

June 4 ‐ 8 (1 week)

Handbook 133 ‐ Instructor Training

Frankfort, KY

Class No. 5183

June 18 (2 hours)

Webinar ‐ Basic Uncertainty Concepts

Class No. 5170

June 18 (2 hours)

Webinar ‐ Documenting Traceability and Calibra‐

tion Intervals

Class No. 5180

June 19 (2 hours)

Webinar ‐ Calibration Report Evaluations

Class No. 5171

June 19 (2 hours)

Webinar ‐ Conducting an Effective Management

Review

Class No. 5172

June 20 (2 hours)

Webinar ‐ NISTIR 6969 SOP 8 Part 1

Class No. 5186

(continued on page 4)

W&M Connection 3 Volume 3 Issue 1

ufactured or placed into service before January 1, 1998, depended on user

supplied measurements for the final moisture result. That is, the operator

must make separate measurements of temperature, volume and/or weight

and apply those measurements in making the final moisture determination.

Some of these meters have interchangeable modules that have to be con‐

nected to and interchanged for different grain types. Some meters need look‐

up tables to determine the final moisture content of the grain sample. Along

with the many user applied measurements and interactions that must be

performed with these moisture meters, the meter calibrations for the various

meter types are based on different prediction equations, and grain sample

sets. All of these factors can affect uniformity among the various meters and

the accuracy of the moisture determination. 

A manual temperature correction is used for many of the meters that were

placed into service before January 1, 1998. For these meters, the user man‐

ually determines the temperature of the grain. The grain moisture reading

is obtained, then the temperature of the grain and moisture reading are com‐

pared to a look‐up table that provides the final moisture results based on the

grain temperature and the moisture reading. Some moisture levels exceed

the look‐up table so the user must calculate the temperature correction and

final moisture result. Any user errors due to improper temperature meas‐

urements, improper use of the look‐up table, incorrect look‐up tables, and

improper calculation of the temperature correction will contribute to errors

in the final grain moisture result.

The weight of the grain is also a factor that will affect the moisture result.

For many of the meters that were placed into service prior to January 1, 1998,

the user must weigh the sample of grain prior to putting the sample in the

grain moisture meter’s hopper. Some of these meters have a scale within

the hopper and the operator must read graduated lines to ensure that the

sample weight is appropriate prior to making the measurement. Errors can

occur due to improper weighing of the grain sample or inoperable or mal‐

functioning built‐in scales. 

Some of these grain moisture meters use “calibration modules”, which are

attachments for the meter that contain the calibrations for various grain

types. These grain specific modules are connected to the meter and are in‐

terchanged by the user based on the various grain types for which the mois‐

ture determinations are made. Inappropriate use of the modules may cause

errors in the test results. 

Some of these meters do not directly indicate percent moisture. For these

meters, a number based on the dielectric reading of the grain sample is ob‐

tained from the device by user‐operated dials on the meter and the number

obtained from the meter corresponds to a moisture value on a look‐up table.

User error due to inappropriate use of the meter and look‐up tables could

lead to errors in the test results of these meters. 

Many of the variations and errors in the results obtained from this earlier

generation of moisture meters could be attributed to operator error and cal‐

ibration sample set variations. 
W&M Connection 4 Volume 3 Issue 1

Dielectric Moisture Meters – Post-1998 Meters

In 1991 a National Type Evaluation Technical Committee (NTETC) Grain Sector

was established to improve the uniformity and accuracy of commercial grain

moisture meters and their associated measurements. As a result of the work

of the Grain Sector, a National Type Evaluation Program (NTEP) for grain mois‐

ture meters was established; a new Code was developed in National Institute

of Standards and Technology (NIST) Handbook (HB) 44 Specifications, Toler‐

ances, and Other Technical Requirements for Weighing and Measuring De‐

vices for field evaluation; and new criteria were developed in National

Conference on Weights and Measures (NCWM), Inc. Publication 14 for NTEP

evaluation of grain moisture meters for meters that were manufactured or

placed into service after January 1, 1998. 

Although there was no change to basic measurement technologies, improve‐

ments were made in commercial moisture determinations because meters

manufactured or placed into service after January 1, 1998, were designed to

meet the new criteria in NIST HB 44 and NCWM Publication 14. Changes to

the design criteria for these meters were such that the operator was no longer

required to determine grain volume, weight, and/or temperature of the grain

sample; these measurements became a function of the meter and eliminated

much of the user errors associated with these measurements. Operating

range criteria for these meters is an automatic function to ensure that meter

moisture determinations are only made within the specified meter and grain

temperature and the grain moisture ranges of the meter. In addition, com‐

mercial meters under the new criteria are required to directly display and

record the moisture content value as percent moisture content to eliminate

errors associated with the use of look‐up tables. 

In addition to new design criteria, the development of the NTEP program for

grain analyzers provides some assurance that grain moisture meters are de‐

signed in accordance with NIST HB 44 before that same pattern or type of

device is used commercially. An added benefit of the NTEP program for grain

moisture meters is the addition of a second phase of NTEP evaluation called

the “Ongoing Calibration Program.” The NTEP program for grain moisture

meters is different than other device evaluations because of these two phases

of evaluation: the NTEP phase I (device evaluation) and the NTEP Phase II

program (ongoing calibration program). In phase I, the device is evaluated

similar to other NTEP device evaluations to ensure that the device meets the

criteria of NIST HB 44 and NTEP Criteria. The NTEP phase II program is a pro‐

gram whereby meter calibrations are tested annually. This annual meter cal‐

ibration addresses the concerns with the calibrations of the older commercial

meters, which were based on varying grain sample sets and different air oven

reference laboratories. The NTEP calibration data is based on a national sam‐

ple set which consists of samples of grain from across the United States and

calibrations for NTEP meters that are aligned to a single air oven laboratory.

This program reduces average differences between different meter models.

The program does little to reduce sample‐by‐sample variability due to inher‐

ent design differences between meter models. 

A New Generation of Grain Moisture Meters 

Although there have been improvements in moisture determination with the

implementation of new criteria and ongoing updates to the calibrations of all

June 20 (2 hours)

Webinar ‐ NISTIR 7383 SOP 18 Part 1

Class No. 5183

June 21 (2 hours)

Webinar ‐ NISTIR 6969 SOP 8 Part 2

Class No. 5185

June 21 (2 hours)

Webinar ‐ NISTIR 7383 SOP Part 2

Class No. 5187

June 22 (2 hours)

Webinar ‐ Control Charts Using PMAP Software

Class No. 5189

June 22 (2 hours)

Webinar ‐ Uncertainties Using Kragten Spread‐

sheets

Class No. 5188

July 15 ‐ 19

National Conference on Weights and Measures

(NCWM) Annual Meeting

Portland, ME

Contact: info@ncwm.net

July 29 ‐ August 2

NCSLI Conference & Symposium 

Metrology and Testing ‐ the Business End of

Metrology

Sacramento, CA

Contact: NCSLI at http://www.ncsli.org/

August 9 (2 hours)

Webinar ‐ Calibration Report Evaluations

Class No. 5175

August 16 (2 hours)

Webinar ‐ Contract Review

Class No. 5176

August 20 ‐ 24 (1 week)

Fundamentals of Metrology

Class No. 5179

August 23 (2 hours)

Webinar ‐ Document Control and Recordkeeping

Class No. 5177

August 30 (2 hours)

Webinar ‐ Proficiency Testing Follow Up Actions

and Root Cause Analysis

Class No. 5181

September 6 (2 hours)

Webinar ‐ Conducting an Effective Management

Review

Class No. 5178

(continued on page 5)
September 10 ‐ 13

NEMAP*

Portland, ME

Contact: Danny Newcombe at

Danny.Newcombe@maine.gov

September 13 (2 hours)

Webinar ‐ Internal Auditing Best Practices

Class No. 5182

September 16 ‐ 20

Western Weights and Measures Association

(WWMA)

Breckenridge, CO

Contact: Mahesh Albuquerque at

mahesh.albuquerque@state.co.us

September 17 ‐ 20

MidMAP*

Sioux Falls, SD

Contact: Brad Stover at

brad.stover@state.sd.us

September 24 ‐ 27

SWAP*

Baton Rouge, LA

Contact: Richert Williams at

richer_w@ldaf.state.la.us

October 15 ‐ 26 (2 weeks)

Mass Seminar

Class No. 5192

October 16 ‐ 17

Northeastern Weights and Measures Association

(NEWMA) Interim Meeting

TBD

Contact: James Cassidy at

jcassidy@cambridgema.gov

October 18 (2 hours)

Webinar ‐ State Laboratory Annual Submission

Process**

Class No. 5190

November 1 (2 hours)

Webinar ‐ State Laboratory Annual Submission

Process **

Class No. 5191

November 5 ‐ 9 (1 week)

Volume Seminar

Class No. 5193

December 3 ‐ 7 (1 week)

Intermediate Metrology Seminar

Class No. 5164

(continued on page 6)

W&M Connection 5 Volume 3 Issue 1

meters manufactured or placed into service after January 1, 1998, described

earlier, there are inherent limitations in dielectric technology. Dielectric mois‐

ture meters are influenced by the grain variety, size, weight, growing seasons,

etc. and different sensing techniques and algorithms are in use by each meter.

As such, separate calibrations for each grain type are needed. Since there

are changes in crops from year to year, the relationship between the meas‐

ured dielectric constant and the moisture are not stable from year to year

and calibrations must be tested annually and adjusted appropriately. The

cost of annual calibrations is exceeding the cost of the meter. The various

sensing technologies have not changed for many years because each meter

type has a specific sensing technology that is used in conjunction with a spe‐

cific algorithm for predicting moisture. To further improve the grain moisture

measurement system, research, which began in 1995, was conducted by the

Agriculture Research Service (ARS) and the U.S. Department of Agriculture

(USDA) in the dielectric response to grain moisture to improve the technology

of dielectric grain moisture determination. 

The radio frequency (RF) range for most commercial meters is 1 to 20 MHz.

The research conducted by ARS and USDA was conducted at a much higher

RF of 1 MHz to 501 MHz. The equipment used to conduct the research were

a test cell, which was developed for the higher frequency, a funnel apparatus,

which was used to adequately repeat fill the test cell, and a HP‐4291A RF Im‐

pedance Analyzer, which was used to measure and record information at the

high frequencies. USDA, Grain Inspection Packers and Stockyards Adminis‐

tration (GIPSA) collected data using this equipment on 3700 samples of grain

that was collected from across the United States through the USDA annual

moisture program. The goal was to get results that agreed closely with the

official air oven moisture analysis. 

One of the purposes of this research was to make a more effective grain mois‐

ture algorithm that could be used across meter types. This would further im‐

prove the uniformity among grain moisture meters. Several tests were

conducted to include tests over wide frequency ranges, density tests at vary‐

ing frequencies and dielectric loss at varying moisture levels. As a result of

this research, it was determined that the 100 MHz to 200 MHz range was the

optimal range for dielectric constant measurements and a unified moisture

algorithm was developed based on a test frequency of 149 MHz. 

With the unified moisture algorithm, meter designs operating at 149 MHz

can be brought into better alignment with appropriate adjustments for grain

density and cell dimensions. What this means for future grain moisture me‐

ters is greater uniformity in results on a sample‐by‐sample basis. 

The results of this research and the unified moisture algorithm was provided

to U.S. grain analyzer manufacturers and state and federal government rep‐

resentatives on August 22, 2001, in a technical presentation on “Theory and

Engineering Aspects of a New Unified Grain Moisture Measurement Algo‐

rithm” presented by Dr. David Funk, USDA, GIPSA. At the current time, NTEP

moisture certificates have been issued for three high frequency meter mod‐

els.

This unified algorithm will likely impact the NTEP Phase II program for grain

moisture meters, since calibrations for these meters will be unified through
2013

January 27 ‐ 30

National Conference on Weights and Measures In‐

terim Meeting

Charleston, SC

Contact: info@ncwm.net

*Invitation Only

**Limited to State Laboratory Program Participants

CONTACTS FORWEBINARS

• Lab Metrology: Val Miller at val.miller@nist.gov or

view the Laboratory Metrology group webpage at: 

http://www.nist.gov/pml/wmd/labmetrology/webi‐

nars.cfm

• Devices: Tina Butcher at tina.butcher@nist.gov

• Laws & Metric: David Sefcik at david.sefcik@nist.gov

or Lisa Warfield at lisa.warfield@nist.gov

Additional details on the above calendar items

can be found at: 

http://ts.nist.gov/WeightsAndMeasures/calendar3.cfm

W&M Connection 6 Volume 3 Issue 1

the new algorithm. The impact of new meter technology, to the extent that

industry migrates to this technology, could mean an end to the need for NTEP

Phase II evaluation for grain moisture meters as it currently exists. This could

impact the NTEP program in 5 to 10 years and even to the extent that the

current 5–year interagency agreement between NIST and GIPSA, which cur‐

rently extends from 2010 to 2014, to fund the NTEP Phase II program, may

no longer be necessary as it currently exists.

Selection of GIPSA’s New Official Meter(s)

The Grain Inspection Advisory Committee (GIAC) is an advisory committee of

the GIPSA, which is comprised of 15 members representing grain producers,

processors, merchandisers, handlers, exporters, consumers, grain inspection

agencies, and scientists. At its November 2009 meeting, the GIAC recom‐

mended that GIPSA evaluate the current moisture calibration for high mois‐

ture rough rice for accuracy when compared to the air oven reference

method. After investigating the 2009 crop calibration, GIPSA reported that

year to year differences and growing conditions in 2009 contributed to inac‐

curacies in the rough rice calibration. GIPSA concluded that improvements

to the official meter’s accuracy for grain samples with inaccuracies, such as

the rough rice calibration, would degrade the overall accuracy and suggested

that, for better official meter calibrations, a new meter technology is needed.

The GIAC recommended that GIPSA move forward with expediency to deter‐

mine the feasibility and selection of a new official moisture meter with a new

measurement technology. GIPSA plans to implement the new technology for

initial grains in May 2013 and implement the new technology for other grains

in September 2013 and later. But, at its December 2011 meeting, the Grain

Inspection Advisory Committee recommended the implementation of the

149 MHz technology for moisture measurements in August 2012 for fall har‐

vest grains.

As the new meter technology is introduced into the market, more uniformity

among meters will further improve the system of commercial grain moisture

measurements. Impacts of this new technology will be discussed in future

Weights and Measures Connection newsletter articles. 

If you have any questions or comments, you may contact Diane Lee by e‐mail

at diane.lee@nist.gov. 

Disclaimer:

Any mention of commercial products within this article is for information only; it

does not imply recommendation or endorsement by NIST.

Did You Know?

An “acre” is a term that denotes area and appears both in the imperial and

U.S. customary measuring systems. Originally the “acre” was the amount

of ground that could be plowed by one man behind an ox in a day.

Before the use of the metric system, many of the European countries had

their own “official” acres. The actual size of an acre could vary significantly

from one country to another. Today, European countires use the hectare.

The NIST

Office of Weights and Measures 

homepage: 

http://www.nist.gov/pml/wmd/index.cfm

Please change your 

browser’s bookmark.

VISIT THE NATIONAL FIRE PRO‐

TECTION ASSOCIATION FOR VALUABLE

TIPS ON WINTER FIRES.

http://www.nfpa.org/categoryList.asp?catego‐

ryID=2103&URL=Safety%20Information/For%20

consumers/Holidays/Put%20a%20Freeze%20on

%20Winter%20Fires&cookie%5Ftest=1

Space heaters, whether portable or staionary, ac‐

counted for one‐third (32 %) of home heating fires

and four out of five (79 %) of home heating fire

deaths.

The leading factor contributing to home heating

fires (26 %) was failure to clean, principally creosote

from solid‐fueled heating equipment, primarily

chimneys. 

(Source: National Fire Protection Association)