# Sec. 5.56.(a)  Grain Moisture Meters

**Section 5.56. has been reorganized into two sections. This Section,
5.56.(a), applies to all NTEP grain moisture meters. It also applies to
any grain moisture meter manufactured or placed into service after
January 1, 1998.** (Code reorganized and renumbered 1996.)

## A.  Application

**A.1.** This code applies to grain moisture meters; that is, devices
used to indicate directly the moisture content of cereal grain and oil
seeds. The code consists of general require­ments applicable to all
moisture meters and specific requirements applicable only to certain
types of moisture meters.

**A.2.** This code does not apply to devices used for in‑motion
measurement of grain moisture content or seed mois­ture content.

**A.3. Type Evaluation** - The National Type Evaluation Program will
accept for type evaluation only those devices that comply with this
code. State enforcement will be based upon the effective dates
identified with each requirement when specific dates are shown.

(Added 1993)

**A.4.** See also Sec. 1.10; General Code requirements.

## S.  Specifications

**S.1. Design of Indicating, Recording, and Measuring Elements.**

> **S.1.1. Digital Indications and Recording Elements.**

(a) Meters shall be equipped with a digital indicating element.

(b) The minimum height for the digits used to display moisture content
    shall be 10 mm.

(c) Meters shall be equipped with a communication interface that permits
    interfacing with a recording element and transmitting the date,
    grain type, grain moisture results, and calibration version
    identification.

(d) A digital indicating element shall not display, and a recording
    element shall not record, any moisture content values before the end
    of the measurement cycle.

(e) Moisture content results shall be displayed and recorded as percent
    moisture content, wet basis. Subdivisions of this unit shall be in
    terms of decimal subdivisions (not fractions).

(f) A meter shall not display or record any moisture content values when
    the moisture content of the grain sample is beyond the operating
    range of the device, unless the moisture representation includes a
    clear error indication (and recorded error message with the recorded
    representation).

(g) On multi-constituent meters (e.g., meters which also measure grain
    protein), provision shall be made for displaying and recording the
    constituent label (such as moisture, protein, etc.) to make it clear
    which constituent is associated with each of the displayed and
    recorded values.

(Added 1995)

> (Amended 1993, 1994, 1995 and 1996)
>
> **S.1.2.  Grain or Seed Kind and Class Selec­tion and Reco­rding.** -
> ­Provision shall be made for selecting and recording the kind and class
> (as appropriate) of grain or seed to be mea­sured.  The means to select
> the kind and class of grain or seed shall be readily visible and the
> kind and class of grain or seed selected shall be clearly and
> definitely identified. Abbreviations for grain types indicated on the
> meter must meet the minimum acceptable abbreviations listed in Table
> S.1.2. Meters shall have the capability (i.e., display capacity) of
> indicating the grain type using a minimum of four characters in order
> to accommodate the four-character abbreviations listed in Table S.1.2.
>
> (Amended 1993 and 1995)
>
> **S.1.3. Operating Range. -** A meter shall automatically and clearly
> indicate when the operating range of the meter has been exceeded. The
> operating range shall specify the following:

(a) **Temperature Range of the Meter.** - The temperature range over
    which the meter may be used and still comply with the applicable
    requirements shall be specified. The minimum temperature range shall
    be 10 C to 30 C. No moisture value may be displayed when the
    temperature range is exceeded. An appropriate message shall be
    displayed when the temperature of the meter is outside its specified
    operating range.

+--------------------+------------+--------------------+--------------+
| ***Table S.1.2.    |            |                    |              |
| Grain Types        |            |                    |              |
| Considered for     |            |                    |              |
| Type Evaluation    |            |                    |              |
| and Calibration*** |            |                    |              |
|                    |            |                    |              |
| ***and Minimum     |            |                    |              |
| Acceptable         |            |                    |              |
| Abbreviations***   |            |                    |              |
+--------------------+------------+--------------------+--------------+
| ***Grain Type***   | ***Minimum | #### *Grain Type*  | ***Minimum   |
|                    | Acceptable |                    | Acceptable   |
|                    | Abbre      |                    | Abb          |
|                    | viation*** |                    | reviation*** |
+--------------------+------------+--------------------+--------------+
| *Corn*             | *CORN*     | *Soybeans*         | *SOYB*       |
+--------------------+------------+--------------------+--------------+
| *Durum Wheat*      | *DURW*     | *Two-rowed Barley* | *TRB*        |
|                    |            |                    |              |
| *Soft White Wheat* | *SWW*      | *Six-rowed Barley* | *SRB*        |
|                    |            |                    |              |
| *Hard Red Spring   | *HRSW*     | *Oats*             | *OATS*       |
| Wheat*             |            |                    |              |
|                    | *HRWW*     |                    |              |
| *Hard Red Winter   |            |                    |              |
| Wheat*             | *SRWW*     |                    |              |
|                    |            |                    |              |
| *Soft Red Winter   | *HDWW*     |                    |              |
| Wheat*             |            |                    |              |
|                    |            |                    |              |
| *Hard White Wheat* |            |                    |              |
+--------------------+------------+--------------------+--------------+
| *Sunflower seed    | *SUNF*     | *Long Grain Rough  | *LGRR*       |
| (Oil)*             |            | Rice*              |              |
|                    |            |                    | *MGRR*       |
|                    |            | *Medium Grain      |              |
|                    |            | Rough Rice*        |              |
+--------------------+------------+--------------------+--------------+
| *Grain Sorghum*    | *SORG      | *Small oil seeds   |              |
|                    | [or]{.u    | (under             |              |
|                    | nderline}* | consideration)*    |              |
|                    |            |                    |              |
|                    | *MILO*     |                    |              |
+--------------------+------------+--------------------+--------------+
| *\[Nonretroactive  |            |                    |              |
| as of January 1,   |            |                    |              |
| 1998\]* (Table     |            |                    |              |
| Added 1993)        |            |                    |              |
| (Amended 1995,     |            |                    |              |
| 1998)              |            |                    |              |
+--------------------+------------+--------------------+--------------+

> \(b\) **Temperature Range of each Grain or Seed.** - The temperature
> range for each grain or seed for which the meter is to be used shall
> be specified. The minimum temperature range for each grain shall be
> 0 C to 40 C. No moisture value may be displayed when the temperature
> range is exceeded. An appropriate error message shall be displayed
> when the temperature of the grain sample exceeds the specified
> temperature range for the grain.
>
> \(c\) **Moisture Range of the Grain or Seed.** - The moisture range
> for each grain or seed for which the meter is to be used shall be
> specified. A moisture value may be displayed when the moisture range
> is exceeded if accompanied by a clear indication that the moisture
> range has been exceeded.
>
> \(d\) **Maximum Allowable Meter/Grain Temperature Difference.** - The
> maximum allowable difference in temperature between the meter and the
> sample for which an accurate moisture determination can be made shall
> be specified. The minimum temperature difference shall be 10 C. No
> moisture value may be displayed when the maximum allowable temperature
> difference is exceeded. An appropriate error message shall be
> displayed when the difference in temperature between the meter and the
> sample exceeds the specified difference. (Added 1993) (Amended 1995)
>
> **S.1.4. Value of Smallest Unit. ‑** The display shall permit
> constituent value determination to both 0.01 percent and 0.1 percent
> resolution. The 0.1 percent resolution is for commercial transactions;
> the 0.01 percent resolution is for type evaluation and calibration
> purposes only, not for commercial purposes.

### S.1.5. Operating Temperature.

\(a\) Warm up period: When a meter is turned on it shall not display or
record any usable values until the operat­ing temperature necessary for
accurate determination has been attained, or the meter shall bear a
conspicuous statement adjacent to the indication stating that the meter
shall be turned on for a time period specified by the manufac­turer prior
to use.

> \(b\) A meter shall meet the requirements of T.2. - Tolerance Values
> when operated in the temperature range of 10 C to 30 C (50 F to 86 F)
> or within the range specified by the meter man­ufac­turer.
>
> \(c\) If the manufacturer specifies a temperature range, the range
> shall be at least 20 C (36 F).
>
> (Added 1993) (Amended 1995 and 1996)

**S.2. Design of Grain Moisture Meters**

> **S.2.1. Minimum Sample Size.** - Meters shall be designed to measure
> the moisture content of representative-size grain samples. The minimum
> allowable sample size used in analysis shall be 100 g or 400 kernels
> or seeds, whichever is smaller.
>
> (Added 1993) (Amended 1995)
>
> **S.2.2. Electric Power Supply.**
>
> **S.2.2.1. Power Supply, Voltage and Frequency.**

\(a\) A meter that operates using alternating current must perform
within the toleran­ces defined in Section T.2. - Tolerance Values over
the line voltage range 100 V to 130 V, or 200 V to 250 V rms as
designed, and over the frequency range of 59.5 Hz to 60.5 Hz.

> \(b\) Battery-operated instruments shall not indicate or record values
> outside the applicable tolerance limits when battery power output is
> excessive or deficient.
>
> **S.2.2.2. Power Interruption.** - A power interruption shall not
> cause an indicat­ing or recording element to display or record any
> values outside the applicable tolerance limits.
>
> (Added 1988)
>
> **S.2.3 Level Indicating Means. -** A meter shall be equipped with a
> level indicator and leveling adjustments if its performance is changed
> by an amount greater than the applicable tolerance when the meter is
> moved from a level position to a position that is out of level in any
> upright direction by up to 5 percent (approximately 3 degrees). The
> level-indicating means shall be readable without removing any meter
> parts requiring a tool.
>
> (Added 1988) (Amended 1994)
>
> **S.2.4. Calibration Integrity**
>
> **S.2.4.1. Calibration Version.** - A meter must be capable of
> displaying either calibration constants, a unique calibration name, or
> a unique calibration version number for use in verifying that the
> latest version of the calibration is being used to make moisture
> content determinations.
>
> (Added 1993)(Amended 1995)
>
> **S.2.4.2. Calibration Corruption.** - If calibration constants are
> digitally stored in an electronically alterable form, the meter shall
> be designed to make automatic checks to detect corruption of
> calibration constants. An error message must be displayed if
> calibration constants have been electronically altered.
>
> (Added 1993) (Amended 1995)
>
> ***S.2.4.3. Calibration Transfer. -** The instrument hardware/software
> design and calibration procedures shall permit calibration development
> and the transfer of calibrations between instruments of like models
> without requiring user slope or bias adjustments.*
>
> *\[Note: Only the manufacturer or the manufacturer\'s designated
> service agency may make standardization adjustments on moisture meters
> This does not preclude the possibility of the operator installing
> manufacturer-specified calibration constants under the instructions of
> the manufacturer or its designated service agency.\] Standardization
> adjustments (not to be confused with grain calibrations) are those
> physical adjustments or software parameters which make meters of like
> type respond identically to the grain(s) being measured.*
>
> *\[Nonretroactive as of January 1, 1999\]*
>
> (Added 1994) (Amended 1998)
>
> **S.2.5. Provision for Sealing. -** Provision shall be made for
> applying a security seal in a manner that requires the security seal
> to be broken, or for using other approved means of providing security
> (e.g., audit trail available at the time of inspection as defined in
> Table S.2.5.\*) before any change that affects the metrological
> integrity of the device can be made to any mechanism.
>
> *\[\*Note: Table S.2.5. is Nonretroactive as of January 1, 1999.\]*
>
> \[Note: Zero-setting and test point adjustments are considered to
> affect metrological characteristics and must be sealed.\]
>
> (Added 1993) (Amended 1995 and 1997)
>
> **S.2.6. Determination of Quantity and Temperature. -** The moisture
> meter system shall not require the operator to judge the precise
> volume or weight and temperature needed to make an accurate moisture
> determination. External grinding, weighing, and temperature
> measurement operations are not permitted.
>
> (Added 1994)(Amended 1995)

**S.3. Accessory Equipment -** When the operating instructions for a
moisture meter require accessory equipment separate from and external to
the moisture meter, such equipment shall be appropriate and complete for
the measurement.

**S.4. Operating Instructions and Use Limitations.** ‑ The manufacturer
shall furnish operating instructions for the device and accessories that
include complete information concerning the accuracy, sensitivity, and
use of accessory equipment necessary in obtaining a moisture content.
Operating instructions shall include the following information:

(a) name and address or trademark of the manufacturer;

(b) the type or design of the device with which it is intended to be
    used;

(c) date of issue;

(d) the kind or classes of grain or seed for which the device is
    designed to measure moisture content;

(e) the limitations of use, including but not confined to the moisture
    mea­surement range, grain or seed tempera­ture, maximum allowable
    temperature difference between grain sample and meter, kind or class
    of grain or seed, moisture meter temperature, voltage and frequency
    ranges, electromag­netic interferences, and necessary accessory
    equipment.

> (Added 1984)

## N.  Notes

**N.1. Testing Procedures.** Field evaluation of grain moisture meters
shall be performed by one of the following methods:

> **N.1.1. Air Oven Reference Method Transfer Standards.** ‑ Official
> grain samples shall be used as the official transfer standards with
> moisture content values assigned by the reference methods.  The
> reference methods shall be the oven drying methods as specified by the
> USDA GIPSA. Tolerances shall be applied to the average of at least
> three measure­ments on each official grain sample.  Official grain
> samples shall be clean and naturally moist, but not tempered (i.e.,
> water not added).
>
> (Amended 1992 and 2001)
>
> **N.1.2. Minimum Test.** ‑ A minimum test of a grain moisture meter
> shall consist of tests:

(a) with samples (need not exceed three) of each grain or seed for which
    the device is used, and

(b) with samples having at least two different moisture content values
    within the operating range of the device.

> (Amended 1986 and 1989)
>
> **N.1.3. Meter to Like‑Type Meter Method Transfer Standards. ‑**
> Properly standardized reference meters using National Type Evaluation
> Program approved calibrations shall be used as transfer standards. A
> reference meter shall be of the same type as the meter under test.
> Tests shall be conducted side‑by‑side using, as a comparison medium,
> grain samples that are clean and naturally moist, but not tempered
> (i.e., water not added).
>
> (Added 2001)

## T.  Tolerances

**T.1. To Underregistration and to Overregistration.** ‑ The tolerances
hereinafter prescribed shall be applied to errors of under registra­tion
and errors of over­registration.

**T.2. Tolerances**

> **T.2.1. Air Oven Reference Method.** ‑ Maintenance and acceptance
> tolerances shall be as shown in Table T.2.1. Tolerances are expressed
> as a fraction of the percent moisture content of the official grain
> sample, together with a minimum tolerance.
>
> (Amended 2001)
>
> **T.2.2. Meter to Like-Type Meter Method. ‑** Maintenance and
> acceptance tolerances shall be as shown in Table T.2.2. The tolerances
> shall apply to all types of grain and seed.
>
> (Added 2001)

  ----------------------------------- -----------------------------------
                                      

  ----------------------------------- -----------------------------------

(Amended 2001) (Table Added 2001)

**T.3. For Test Weight Per Bushel Indications or Recorded
Re­presenta­tions. ‑** The maintenance and acceptance tolerances on test
weight per bushel indications or recorded representations shall be
0.193 kg/hL or 0.15 lb/bu. The test methods used shall be those
specified by the USDA GIPSA.

(Amended 1992)

## UR. User Requirements

**UR.1. Selection Requirements.**

> **UR.1.1. Value of the Smallest Unit on Primary Indicating and
> Recording Elements.** - The resolution of the moisture meter display
> shall be 0.1 percent moisture during commercial use.
>
> **UR.1.2. See G-UR.1.2.**

**UR.2. Installation Requirements. -** The grain moisture meter shall be
installed in an environment within the range of temperature and/or other
environmental factors specified in the operating instructions.

**UR.3. Use Requirements.**

> **UR.3.1. Operating Instructions.** - The operating instructions for
> the use of the grain moisture meter shall be readily available to the
> user, service technician, and weights and measures official at the
> place of installation. It shall include a list of accessory equipment
> and the kinds of grain or seed to be measured with the moisture meter.
>
> (Amended 1988)
>
> **UR.3.2. Other Devices not used for Commercial Mea­sure­ment.** ‑ If
> there are other moisture meters on the premises not used for trade or
> deter­mining other charges for services, these devices shall be clearly
> and conspicuously marked \"Not for Use in Trade or Commerce.\"
>
> **UR.3.3. Maintaining Integrity of Grain Samples.** ‑ ­When­ever there
> is a time lapse (temperature change) between taking the sample and
> testing the sample, means to prevent condensation of moisture or loss
> of moisture from grain samples shall be used.  For example, a cold
> grain sample may be kept in a closed container in order to permit the
> cold grain to come to the operating temperature range of the meter
> before the grain moisture measurements are made.
>
> **UR.3.4. Printed Tickets.**

\(a\) Printed tickets shall be free from any previous indication of
moisture content or type of grain or seed selected.­

\(b\) The customer shall be given a printed ticket showing the date,
grain type, grain moisture results, and calibration version
identification. The ticket shall be generated by the grain moisture
meter system.

> (Amended 1993 and 1995)
>
> **UR.3.5. Accessory Devices.** ‑ Accessory devices, if neces­sary in
> the deter­mination of a moisture content value, shall be in close
> proximity to the moisture meter and allow immediate use.
>
> **UR.3.6. Sampling.** ‑ A grain sample shall be obtained by following
> appropriate sampling methods and equipment.  These include, but are
> not limited to grain probes of appropriate length used at random
> locations in the bulk, the use of a pelican sampler, or other
> techniques and equipment giving equivalent results. The grain sample
> shall be taken such that it is representative of the lot.
>
> **UR.3.7. Location.** ‑ See G‑UR.3.3.
>
> **UR.3.8. Level Condition.** - If equipped with a level indicator, a
> meter shall be maintained in a level condition.
>
> (Added 1988)
>
> **UR.3.9. Current Calibration Data.** - Grain moisture determina­tions
> shall be made using only the most recently published calibration data.
>
> (Added 1988)
>
> **UR.3.10. Posting of Meter Operating Range.** - The operating range
> of the grain moisture meter shall be clearly and conspicuously posted
> in the place of business such that the information is readily visible
> from a reason­able customer position. The posted information shall
> includ­e the following:

\(a\) The temperature range over which the meter may be used and still
comply with the applicable requirements. If the temperature range varies
for dif­ferent grains or seed, the range shall be specified for each.

\(b\) The moisture range for each grain or seed for which the meter is
to be used.

\(c\) The temperature range for each grain or seed for which the meter
is to be used.

\(d\) The maximum allowable difference in temperature that may exist
between the meter and the sample for which an accurate moisture
determination can be made. (Added 1988)

+---------------------------+------------------------------------------+
| ***Table S.2.5.           |                                          |
| Categories of Device and  |                                          |
| Methods of Sealing***     |                                          |
+---------------------------+------------------------------------------+
| ***Categories of          | ***Method of Sealing***                  |
| Device***                 |                                          |
+---------------------------+------------------------------------------+
| *Category 1: No remote    | *Seal by physical seal or two event      |
| configuration             | counters: one for calibration parameters |
| capability.*              | (000 to 999) and one for configuration   |
|                           | parameters (000 to 999). If equipped     |
|                           | with event counters, the device must be  |
|                           | capable of displaying, or printing       |
|                           | through the device or through another    |
|                           | on-site device, the contents of the      |
|                           | counters.*                               |
+---------------------------+------------------------------------------+
| *Category 2: Remote       | *The hardware enabling access for remote |
| configuration capability, | communication must be at the device and  |
| but access is controlled  | sealed using a physical seal or two      |
| by physical hardware.*    | event counters; one for calibration      |
|                           | parameters (000 to 999) and one for      |
| *A device shall clearly   | configuration parameters (000 to 999.)   |
| indicate that it is in    | If equipped with event counters, the     |
| the remote configuration  | device must be capable of displaying, or |
| mode and shall not be     | printing through the device or through   |
| capable of operating in   | another on-site device, the contents of  |
| the measure mode while    | the counters.*                           |
| enabled for remote        |                                          |
| configuration.*           |                                          |
+---------------------------+------------------------------------------+
| *Category 3: Remote       | *An event logger is required in the      |
| configuration capability  | device; it must include an event counter |
| access may be unlimited   | (000 to 999), the parameter ID, the date |
| or controlled through a   | and time of the change , and the new     |
| software switch (e.g.,    | value of the parameter (for calibration  |
| password).*               | changes consisting of multiple           |
|                           | constants, the calibration version       |
| *When accessed remotely   | number may be used rather than the       |
| for the purpose of        | calibration constants). A printed copy   |
| modifying sealable        | of the information must be available     |
| parameters, the device    | through the device or through another    |
| shall clearly indicate    | on-site device. The event logger shall   |
| that it is in the         | have a capacity to retain records equal  |
| configuration mode and    | to twenty-five (25) times the number of  |
| shall not be capable of   | sealable parameters in the device, but   |
| operating in the          | not more than 1000 records are required. |
| measuring mode.*          | (Note: Does not require 1000 changes to  |
|                           | be stored for each parameter.)*          |
+---------------------------+------------------------------------------+
| *Category 3a: No remote   | *Same as Category 3*                     |
| capability, but operator  |                                          |
| is able to make changes   |                                          |
| that affect the           |                                          |
| metrological integrity of |                                          |
| the device (e.g., slope,  |                                          |
| bias, etc.) in normal     |                                          |
| operation.*               |                                          |
+---------------------------+------------------------------------------+
| *Category 3b: No remote   | *Same as Category 3*                     |
| capability, but*          |                                          |
|                           |                                          |
| *access to metrological   |                                          |
| parameters is controlled  |                                          |
| through a software switch |                                          |
| (e.g., password).*        |                                          |
+---------------------------+------------------------------------------+
| \[*Nonretroactive as of   |                                          |
| January 1, 1999.\]*       |                                          |
| (Amended 1998)            |                                          |
+---------------------------+------------------------------------------+