U.S. Department

of Commerce

National Bureau

of Standards

NBSIR

80-2179 'f

December 1980

Type Approval

Criteria and

Test Procedures

Prepared for the Task Force on

National Type Approval of the

National Conference on

Weights and Measures

NBSIR 80-2 1 79

TYPE APPROVAL

CRITERIA AND

TEST PROCEDURES

Prepared for the Task Force on

National Type Approval of the National Conference on

Weights and Measures

December 1980

U.S. DEPARTMENT OF COMMERCE, Philip M. Klutznick, Secretary

Jordan J. Baruch, Assistant Secretary for Productivity, Technology, and Innovation

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
» • *
FOREWORD

This document is a preliminary draft of a handbook on type approval

criteria and procedures for weighing and measuring devices. The

distribution of the draft is to solicit comments on whether the

information is useful to manufacturers and weights and measures

officials. The responses will determine if further development of

written type approval criteria in the measurement areas covered in

the draft and in other measurement areas should be pursued.

The development of checklists and test procedures is an effort to

make both the manufacturer and the enforcement official aware of

criteria currently being used in type approval examinations. It is

also an attempt to standardize the criteria and test methods. The

distribution of this draft document will provide a basis for discussion

of possible directions for a national type approval program in the

future. The checklists and test methods are intended to be sufficiently

flexible to be easily changed to keep pace with technology and to permit

innovation in the design of weighing and measuring equipment.
.
UNITED STATES DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, D C. 20234

November 12, 1980

MEMORANDUM FOR Task Force on National Type Approval

Specifications and Tolerances Committee

Directors of Weights and Measures

Industry Representatives

From: Henry V. Oppermann <- >—

General Physical Scientist/^ ' ^

Office of Weights and Measures

Subject: Draft Type Approval Criteria and Test Procedures

Uniform criteria and test procedures are necessary for a national type

approval program. Drafts of checklists of type approval criteria and

test procedures have been developed to aid in achieving reciprocity

between jurisdictions. The drafts have also been prepared to inform

manufacturers of the criteria and tests to be applied to devices submitted for type approval.

The drafts of the checklist for digital weighing equipment (item II),

the performance tests (items VI through X), and the use of error weights

with digital scales have been discussed by California, Federal Grain

Inspection Service (FGIS), and Office of Weights and Measures (OWM)

representatives and serve as the basis for reciprocity between organizations. The remaining drafts are in an early stage of development and are still being revised to establish a foundation for reciprocity between

the organizations.

Eventually these drafts are intended to become the basis of a national

type approval program. The drafts are being circulated for review and

comment to obtain input from industry and enforcement representatives.

Enforcement officials, especially those conducting their own type

approval program, should review the drafts to determine if devices meeting the checklist criteria and passing the tests would satisfy their type

approval requirements. They should also decide if they would accept the

examination of a jurisdiction that has been trained in conducting a type

approval examination using the checklists and test procedures, thereby

eliminating duplicate type approval examinations. If a jurisdiction has

any additional requirements, they should be sent to the Task Force on National Type Approval for possible incorporation into the checklists or procedures. Manufacturers should comment specifically whether or not the

criteria are reasonable and the test procedures practical.

All items in the drafts are considered subject to change based upon the

comments that are received. Comments on the operation of the current

reciprocity program and recommendations for future development are encouraged.
The plan for future development of the type approval program, criteria,

and procedures is as follows. The criteria and procedures along with

comments received will be submitted to the Task Force on National Type

Approval for evaluation. The Task Force will recommend changes in

criteria and procedures and provide guidance for future program development. The Specifications and Tolerances Committee (S&T) will serve as the overseeing body to assure that the criteria and procedures are con- sistent with the requirements of MBS Handbook 44 and the intent of the

Conference. Criteria and procedures that are challenged and cannot be

resolved through the Task Force will be taken to the S&T Committee for

resolution. Any issues that cannot be resolved through the S&T Committee

will be submitted to the National Conference on Weights and Measures

(NCWM) for a vote and possible inclusion in Handbook 44.

The checklists are much more specific than Handbook 44. They are the

result of decisions made in type approval examinations or reflect

problems that have been experienced in examinations. The digital weighing equipment checklist reflects criteria that are currently being used

in type approval examinations.

The checklists are to serve as a guide in product design so that a manufacturer can be aware of decisions that already have been made in

previous examinations. The checklists are intended to be more flexible

than Handbook 44. The checklists are not intended to stifle manufacturer

innovations. If a manufacturer develops a new capability or new approach

to a method of operation or develops a new argument on a previously decided

issue and can convince the S&T Committee of its merit, the checklist will

be changed. An issue that is strongly contested by industry or enforcement

officials can be taken before the NCWM for resolution. The checklists are intended to make the manufacturer aware, before production has been initiated,

of criteria that will be applied to a device. Ideally, any conflicts with

the criteria can be resolved in the design stage before considerable expense

must be incurred to modify a unit.

THE CHECKLISTS ARE NOT TO BE USED BY WEIGHTS AND MEASURES OFFICIALS TO CHECK

DEVICES CURRENTLY INSTALLED IN COMMERCIAL APPLICATIONS. The checklists are continually updated as new criteria are developed in type approval examinations. Devices currently in use may not have been tested against some of the criteria given in the checklists so it is not appropriate to apply

the criteria retroactively. It is appropriate for the checklists to be used

in an examination of new equipment that is being submitted to the State for

type approval for the first time.

Apparently some misunderstandings exist about how companies can obtain Reports

of Test or Certificates of Approval from California, FGIS, and NBS under the

reciprocity program and the devices for which a reciprocity agreement exists.

Reciprocity has been achieved between California and NBS on the most common

digital weighing equipment. Digital weighing equipment for which reciprocity

has not yet been achieved are hopper automatic batching systems, livestock,

bel t-conveyor, and railroad scales. Any unusual weighing equipment must be

examined by each agency.
Reciprocity between FGIS and NBS is nearing the final stages for grain hopper

scales and automatic weighing systems. California is currently reviewing the

FGIS checklist prior to comment.

The appropriate form for testing for compliance with the permanence requirement

(G-S.5.2.5) is currently being evaluated by both MBS and California. The draft

proposal contains three options for consideration by the Task Force. It is

the intent to actively work toward mutually agreeable guidelines by the concerned

agenci es

.

In the interim, California will continue to require a field permanence test for

larger scales. NBS does not perform such tests. Consequently, if a request

for prototype examination is received by OWM without a request for joint

certificate of approval with California, OWM will not include a field permanence

test as part of its examination. California Type Approval would require the field

permanence test to be performed in addition, but would not repeat the OWM tests.

The same is true of FGIS where their requirements are different from Handbook 44.

To receive a Report of Test from two or more agencies based upon a single

examination, it is necessary that a letter (or copies) be sent to each agency

which is to issue a Report for the device being submitted for type approval.

The letters must be received before an examination is initiated to permit the

agencies to discuss the device before the testing begins so that specific tests

can be conducted to satisfy any particular needs of the other agencies. Reciprocal

Reports of Test will not be issued retroactively on any devices.

It is hoped that the Task Force will be able to facilitate resolution of

different requirements between agencies so that ultimately the standard examination conducted by one agency will automatically satisfy the requirements of

another agency. Changes to Handbook 44 and State and Federal regulations will

ultimately be necessary to achieve this goal.

If reciprocity is desired between California and NBS on a device submitted for

type approval, digital weighing equipment may be submitted to either NBS or California. If the equipment is submitted to NBS and is one for which

permanence testing (to certify compliance with G-S.5.2.5) is necessary in the

field, then the device will have to receive this field test in California since

OWM is not presently set up to perform such tests.

Hopper scales and automatic weighing systems for which joint NBS and FGIS

approval is desired should normally be submitted to FGIS for examination.

A joint meeting of the Task Force on National Type Approval and the S&T Committee

is scheduled to be held January 14 from 1:00 - 5:00 p.m. as part of the interim

meetings of the NCWM. The NCWM interim meetings will be held January 14 - 17, 1981

at Texas A&M University, College Station, Texas. All interested parties are

invited to attend and participate. Any topics may be brought up for discussion.

Specific topics scheduled for discussion are:

v
1. Current operation of type approval programs and the

reciprocity program

2. Establishment of specific goals and directions for

a national type approval program

3. Review of comments, checklists, and procedures

4. Discussion of permanence test requirements.

Written comments on the above items are encouraged and should be sent to the

Office of Weights and Measures by January 1, 1981 so they may be summarized and

available to the Task Force members at the interim meetings.

vl
TABLE OF CONTENTS

Page

I. Status of Draft Criteria and Procedures ' 1

II. Checklist for Digital Weighing Equipment 3

III. Checklist for Retail Motor Fuel Devices 39

IV. Checklist for Electronic Hopper Scale 55

V. Procedure for Dynamic Testing of Bulk Weighing Systems 59

and Automated Batch Controllers

A. Test of Static Scale to be Used for Checkweighing

B. Procedure for the Dynamic Test

VI. Permanence Performance Testing for Scales and Electronic 66

Cash Registers

VII. Laboratory Permanence Test for Scales 68

VIII. Performance Tests for a Vehicle Scale and Axle Load

Weighing Element 76

IX. Performance Tests for Platform Scales Except Vehicle,

Railroad, Livestock, and Digital Counter (Bench)

Scales 74

X. Performance Tests for Digital Counter (Bench) and

Price Computing Scales 77

XI. Guideline: Use of Error Weights on Digital Scales 79

XII. Test of a Digital Scale Using Error Weights 81

I. Status of Draft Criteria and Procedures

Checklist for Digital Weighing Equipment

This is an update and revision of two previous checklists that have

been used in type approval examinations over the past three years. The

revision was discussed in detail by California, Federal Grain Inspection

Service (FGIS), and the Office of Weights and Measures (OWM) representatives

at a meeting in August. This draft is currently under review by all parties.

The draft is considered near completion.

Checklist for Retail Motor Fuel Devices

This is the second draft of the checklist. The initial draft was reviewed at the August meeting. This draft is currently under review.

It is expected to be expanded and undergo further revisions.

Checklist for Electronic Hopper Scales

This draft contains type approval criteria and considerations specifically

related to electronic hopper scales. These considerations are in addition to

the Checklist for Digital Weighing Equipment. The relationship of this

checklist with the checklist used by FGIS in its type approval examination will

be reviewed. This is the second draft. Further revisions are expected.

Procedure for Dynamic Testing of Bulk Weighing Systems and Automated Batch

Controllers

This test is currently being utilized in California on aggregate weighing

systems. This item is included to obtain comments on the potential benefit

of the test and the feasibility of the procedure.

Permanence Performance Testing for Scales and Electronic Cash Registers

This draft summarizes the current testing needed to verify the permanence

of a device necessary to fulfill reciprocity considerations in type approval

examinations. It identifies which devices are subject to permanence tests.

Comments are requested on the three different tolerance applications and

time periods involved. Ultimately, one set of parameters will be selected

and applied to weighing equipment.

Laboratory Permanence Test for Scales

The permanence test for some devices can be performed in the laboratory.

The procedures are the basis of agreement between California and OWM to

achieve reciprocity in laboratory tests. The procedure has been used for

many years in OWM laboratory permanence tests.

Performance Tests for a Vehicle Scale and Axle Load Weighing Element

The test procedure outlined in the draft is the test method that has been

used by OWM for many years. The subsequent permanence tests have been added

to achieve reciprocity.

1
Performance Tests for Platform Scales Except Vehicle, Railroad, Livestock,

and Digital Counter (Bench) Scale? *

The test procedure outlined in the draft is an abbreviated version of

the testing currently performed in OWM examinations. The test procedure

has been shortened in recognition of the permanence test that has been

added to achieve reciprocity.

Performance Tests for Digital Counter (Bench) and Price Computing Scales

This draft explains when a laboratory permanence test may be performed

and also provides a field permanence test when the laboratory test cannot

be performed. It is expected that the laboratory test will normally be

performed.

Guideline: Use of Error Heights on Digital Scales

This draft reflects the philosophy that a digital scale may be tested

either by direct reading or by using error weights. If error weights are

used then the one-half scale division permitted for direct reading is not

applied. The draft gives guidelines of when error weights should be used

so that the size of the scale division will not hinder evaluation of the

scale performance and when direct reading may be used for increased efficiency

without affecting the evaluation of device performance.

Test of a Digital Scale Using Error Weights

This paper explains how to test a digital scale using error weights.

The paper is near its finished form.

2
Type Approval Checklist for

Compliance Evaluation of Digital Weighing Equipment

Lab Test j | Field Test [ Conducted by:

Manufacturer : Name

Address

Date:

Location:

Zip.

Telephone

Representative

Prototype device f~ | or Production device

[ Equipment

Type: Mechanical 1I Electromechanical

(e.g. lever) (e.g. lever-tronic)

Electronic

If electronic, type of technology

(e.g. microprocessor)

Capacity x d

d

lb kg

Model Serial No. Manufacturer

Weighing Element

Indicating Element

Control Element

Printing Element

If applicable: platform size

number of sections

section capacity

Load Cell Data

Type: Tension [ 1 Compression [ |

Model Capacity

Quantity Output (m V/V)

Excitation Voltage Dead Load (mV)

Live Load (mV) uV/d^)

Comments:

3
SYSTEM INFORMATION

Standard Features

1 .

2 .

3.

4.

5.

6 .

Optional Features

1 .

2 .

3.

4.

5.

6 .

Examination Checklist - Digital Electronic Scales

Scale Code Requirements

(Code references are for Handbook 44 and California regulations)

Zero Indication Compl ies?

Code References S.1.1. G-S .5.1. CA 3011.1.1.

avoi rdupoi s/metri c sel ecti on (lb/kg)

External

| | Internal | 1

Not appl icabl e

1 1

1 . The width of zero must be £ 1 . 0 d^

avoi rdupoi s

:

Record actual zero width d

d

Yes No N/A

metric: Record actual zero width d

d

Yes No N/A

other units: unit zero width d

d

Yes No N/A

2. A + or - sign should not appear

when the scale is indicating zero. avoidupoi

s

Yes No N/A

metric Yes No N/A

other units Yes No N/A

Note: A plus sign for positive numbers is

discouraged since an unsigned number is

considered to be positive.

3. If a center of zero light is provided, it

must define the center of zero to + 1/4 d . or better. (The center of zero light itself

is optional.) Yes No N/A

4
Compl i es?

4. The zero indication must consist of at

least the following minimum indications,

as appropriate:

a. One digit to the left and all digits to

the right of a decimal point Yes No N/A

b. If a decimal point is not used, at least

one active decade plus any constant (fixed) zeros Yes No N/A

Examples: Capacity Minimum zero indication

25 x .01 lb 0.00 lb

5000 x 1 lb 01b

100 000 x 20 lb 00 lb

Any of the following methods may be used to

indicate a negative balance condition.

a. Displaying negative numbers Yes No N/A

b. Blanking the display Yes No N/A

Note 1: This method cannot be used if the

device also blanks the display to

indicate over-capacity and the load

condition of the load-receivingelement is not evident to the operator;

e.g., a hopper scale where the operator

cannot see the load condition (empty or full) of the hopper. It is recommended

that the indicator also have an annunciator

to indicate "power on" so the operator does

not think the power has been lost.

Note 2: If the device is equipped with a tare

capability, when in the net weight

display mode, the device must indicate

negative net weight values when the gross

weight is less than the tare value.

c. A display of a symbol which cannot be interpreted

as a quantity value; e.g., -, , EEEE, Err,

E S-l , etc. Yes No N/A

Note: Flashing zeros or -00 is not acceptable.

d. Display of complement weight values in excess of

scale capacity; e.g. , for a 120 000 x 20 lb

capacity scale, if the scale is 20 lb behind zero,

the display may indicate 999 980 lb. Yes No N/A

Note: This method may be used only when the

indication is not confusing.

5
Digital Indications - Zone of Uncertainty

Code Reference S. 1 .4.

The zone of uncertainty must be £ 0.3 d ,. Test Complies?

under the following conditions and record the

width of the zone of uncertainty.

a. Near zero: avoirdupois d

d Yes No N/A

metric Cl CL Yes No N/A

other units d

d

Yes No N/A

b. Near capacity: avoirdupois d

d

Yes No N/A

metric d

d

Yes No N/A

other units d

H Yes No N/A

Capacity Indication

Code References S. 1.4.1. CA 3011.1.4.1

A scale is not permitted to indicate or record

weight values when the gross load exceeds 105 %

of the nominal scale capacity. This requirement

applies regardless of how the scale is manipulated

to achieve this condition. Flashing weight values

above capacity is not acceptable as an overload

indication. Compliance should be tested for both

indicating and recording weight values under the

following conditions in all weight units.

Nominal system capacity lb kg

other units

1.

With the scale at zero load, record the last

number displayed before blanking or giving

the overload indication.

lb kg other

2. Enter the maximum tare value permitted. Does the

scale give the overload indication within the

specified gross load limit?

3. If the scale can rezero loads up to scale capacity, rezero a load that exceeds 5 % of the scale capacity.

Does the scale give the overload indication within

the specified gross load limit? Yes No N/A

Yes No N/A

Yes No N/A

6
Compl ies?

4. If the scale limits the amount that can be

rezeroed in one push button zero operation

but the operation can be repeated several

times, rezero weight of approximately 5 % . of the scale capacity. Does the scale give

the overload indication within the specified

gross load limit?

5. If the scale rezeros itself after a power

interruption, place a load on the scale that

will be rezeroed and interrupt the power.

Under this new zero, does the scale give the

overload indication within the specified

gross load limit?

6. A scale should not indicate or record weight

values if the load receiving element rests

on its protective movement limiting stops.

Values Displayed, Temperature Conditions

Code Reference S.l.4.2.

Devices should not indicate or record weight values

yptil the operating temperature necessary for accurate

weighing and a stable zero balance condition has been

attained. Compliance with this section will be determined

under the following conditions;

1. The requirement will not be applied to a device that is

activated at the time of installation.

2. The automatic zero setting mechanism, if provided, will

be permitted to be operational at the time of test.

3. The tests for compliance with this requirement should

be performed at temperatures between 40-80°F.

Yes No N/A

Yes No N/A

Yes No N/A

Either condition a or b must be met.

Is power maintained to the load cel Is at all times? Yes No N/A

Is

the

the device accurate when

scale is operational?

power is turned on and

Yes No N/A

Test method: The test will simulate a normal weighing

operation; it is not based upon a complete test of the

scale. First, if the scale has a power switch, turn on the power to the scale. As soon as the scale is

operational, place a test load of one-half scale capacity

7
on the load receiving element. If a sufficient number

of test weights are not available to reach one-half

scale capacity, use the maximum amount of test weights

available. Place the weights on the scale over a short

period of time to approximate normal loading as close

as possible. Leave the weights on the scale for the

time used in a normal weighting operation. The weight

indication must be within tolerance. Remove the test

load. The scale must return to zero within the minimum

tolerance to be applied to the scale. For direct reading of a digital scale, this will usually be a tolerance

of one division. The scale must maintain a stable zero balance. If desired, the test load may be reapplied to

the load receiving element.

Equipment that is designed to maintain power to the load

cell when the power switch for the weight display is

turned off will be considered to comply with the requirement.

Customer's Indications - Digital Computing Scales

Code References S.l.6.3 CA 3011.5.2.

1. If the operator's side of the scale indicates the

net weight, unit price, and total price, the customer's

side must be similarly equipped.

2. Customer price displays must be in unit price terms

only; i.e., fractional pricing (e.g., 1/4 lb or 1/2 lb) or multiple pound (e.g., 3 lb/$1.00) is not permitted.

Note 1: California permits 1/4 lb and 1/2 lb pricing.

Note 2: Multiplier keys are permitted.

Provision for Sealing Adjustable Components

on Electronic Devices

Code Reference S.1.8.

Are electronic scale calibrating controls (other than

the fine zero balance adjustment) or access to such

controls supplied with provision for sealing? Yes No N/A

Note: Handbook 44 permits the use of the pressure

sensitive seals in additon to lead and wire seals.

(See the definition of security seal in the General

Code.) California and FGIS require the use of lead

and wire seals.

Describe how the device is to be sealed.

Yes No N/A

Yes No N/A

no
Zero Load Adjustment - General

Code References S.2.1.1. CA 3011.2.1.1. Comp! ies?

Indicate the zero adjustment method.

(a) Tool operated zero adjustment

(b) Push button zero

(c) Power switch zero adjustment

1. If the device has push button or power switch

zero, does it comply with the motion detection

requirements of S.2.I.2.?

2. If a digital scale has an analog zero adjustment

mechanism, is the range of the analog zero Id or less?

(G-S.2. Fraud Considerations)

3. For counter (bench) and computing scales used in

direct sales, does motion detection prevent

rezeroing when the platform is being raised or pushed down by hand?

Automatic Zero Setting Mechanism (AZSM)(Zero Tracking)

Code Reference S.2.1.3.

Indicate the status of the AZSM capability.

(a) No AZSM capability | | (b) AZSM is always operational | | (c) AZSM may be activated or deactivated by an external

switch

| | (d) AZSM may be activated or deactivated by an internal

switch or selected by programming at the time of

installation

| | (e) The size of the AZSM operature is selectable j |

If the device has an AZSM capability, record the size of

the aperture.

(a) avoirdupois d

d

(b) metric d

^ (c) other units d^

Does the size of the aperture comply with S.2.1.3.

for the intended application? Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

9
For S.2.1.3. Compl ies?

Note: For devices falling under S.2.1.3. (a),. AZSM may

be operable with the device at a gross load zero,

a net load zero, or a negative net weight indication

resulting from a tare weight entry>and the scale

at zero gross load. AZSM should not be operable

on any hopper scale. Devices falling under S.2.1.3

(b) and (c) are permitted to have AZSM operable only

at a gross load zero.

AZSM is not to be operational when the scale is

displaying a positive weight value.

Zero-Load Adjustment - Monorail Scales

Code Reference S.2.1.4.

1. Means must be provided for setting the zeroload balance and any tare value less than 5%

of the scale capacity to within 0.02% of scale

capacity. Yes No .N/A

For an in-motion system, the conditions above

must be automatically maintained. Yes No N/A

Tare Mechanism

Code Reference S.2.1.4.

The tare mechanism shall operate only in the

direction of underregistration; i .e.

,

a negative

number should not be taken as tare. Yes No N/A

Test method for push button (platter) tare:

Rezero (using the zeroing mechanism) a small

load and remove the load. This will result

in a behind-zero indication. Attempt to take

this value as tare using the push button. It

should not be accepted as tare.

A tare entry of zero should not result in an indication that tare has been taken. Yes No N/A

(G— S .5.1. Consideration)

A minimum net load of 20 divisions should be

required before a computing scale automatically

clears a tare entry. Yes No N/A

(G-S.5. Consideration: This is not a requirement.)

A prepackaging or computing scale that takes tare

to the same resolution as the displayed scale

division, for example 0.01 lb, may result in a

10
significant bias on packages utilizing the same Comp! ies?

tare material. For example, suppose a large

number of packages is being prepared and the

actual weight of the tare is 0.024 lb. If the

scale can only take tare as 0.02 lb, the packages

will have a bias toward short weight of 0.004 lb.

This is readily detectable on the 5 lb x .002 lb even arm balance used to check small packages.

It is recommended that scales used for prepackaging be able to take tare to + 1/4 of the

displayed scale division. This would reduce

package errors due to the rounding of the tare

weight.

Record whether or not the push button tare is

taken to a higher resolution than the displayed

scale division.

Yes | | No [ [ Test method: Place a load on the scale so that the

scale is near the breakpoint on the upper half of

the scale division. Weights representing less than

1 d , will probably have to be used. Tare off this load.

Determine if the net weight zero reference point is near the center of the net weight zero indication.

If it is, the tare was taken to a resolution better

than 1 d,.

d

Leveling Indicating Means - Portable Scales

Code References S.2.3. CA 3011.2.3.

Is the device equipped with a level indicator as standard equipment?

Yes | | No

[ (

1. If not, does the device comply with the provisions

of S.2.3.? Yes No N/A

The test procedure is given in "Performance Tests

for Digital Counter (Bench) and Price Computing

Scales".

2. Is the level-indicating means readily observable

without mechanical disassembly that requires the use of tools? Yes No N/A

11
Compl ies?

3. Portable scales must have a means of leveling

the device;e.g., adjustable legs. Yes No N/A

Damping Means

Code References S.2.4. CA 3011.2.4.

Is the device equipped with an effective means for

damping oscillations? Yes No N/A

Electronic (Recording) Elements

Code Reference S.2.4.1.

Is the electronic indicating element equipped with

or may it be equipped with a recording element?

Yes No Q

If yes, does it comply with the motion detection

requirements of S.2.3.I.? Test for both large

and small (10 d^) changes in weight. Yes No N/A

Design of Load - Receiving Elements - Drainage

Code References S.3.2. CA 3011.3.2.

If the load-receiving element is designed to receive

wet commodities, is it designed to drain effectively? Yes No N/A

Design of Weighing Elements - Antifriction Elements

Code Reference S.4.1. CA 3011.4.1.

Are frictional effects reduced to a minimum in the

weighing element? Yes No N/A

For platform scales: Is interference between

platform and frame prevented? Yes No N/A

Multiple Load - Receiving Elements

Code Reference S.4.3. CA 3011.4.3.

Can the indicating or recording element be coupled

to two or more load-receiving elements with

independent weighing systems?

Yes | | No ) |

12
Compl i es?

If yes, does the indicating element:

(a) Automatically indicate which loadreceiving element is in use? Yes No N/A

(b) Prohibit the activation of any

load-receiving element not in use? Yes No N/A

Marking Requirements - Nominal Capacity

Code References S.6.1. CA 3011.6.1.

1.

The nominal capacity by minimum division in all

externally selectable weight units is to be

clearly and conspicuously marked adjacent to the

weight display.

2.

The marking must be permanent.

Yes No N/A

Yes No N/A

Note: Permanence of the capacity marking is less stringent

than for the identification badges. Ideally, this

information should be silk-screened on the front

panel adjacent to the weight display. Occasionally

this information is applied at the time of installation,

An external decal stating the capacity by division

size may be used provided it is likely to remain on the device under normal use. If a decal is damaged

or becomes illegible it must be replaced. A DYMOtype tape label is not considered acceptable for

production devices. The capacity by minimum division

may be stated on a strip of paper provided it is

placed inside the device adjacent to the weight

display and is protected from external influences

that could damage the paper or obliterate the

1 etteri ng

.

3. The capacity by division size must be marked for all

externally selectable weight units; e.g,, in both

pounds and kilograms.

4. Does the scale display weight values up to and

including its marked capacity?

Yes No N/A

Yes No N/A

Note 1: A scale must display the weight value

equal to its rated capacity. For

example, a scale that can display to

only 199.9 lb cannot be marked 200 x 0.1 lb

Note 2: Scales with variable resolution must be

marked with the weight ranges and corresponding division sizes.

Example: 0-3 kg ( 6 lb) x 1 g (0.002 lb)

3-6 kg (15 lb) x 2 g (0.005 lb)

6-15 kg (33 lb) x 5 g (0.01 lb)

13
Compl ies?

Note 3: This requirement applies to digital

indicating elements and to customer's

indications on computing scales. Remote

displays which provide the only weight

indication must also be marked. The

customer weight display provided for scales

interfaced with electronic cash registers

(ECRs) must be marked. Weight displays

which are built into ECRs must also be

marked. Large remote customer ("scoreboard")

displays have not been required to meet the

marking requirements because the markings

probably could not be read from a customer's

position. In this case the operator's

weight display must be properly marked.

Marking - Special Applications

Code References S.6.2. CA 3011.6.2.

The philosophy of this requirement is that devices

which are designed specifically for special applications are to be marked for the application. This

is intended to prevent the device from being used

in an application where it is not suitable.

Although the requirement is written for prepackaging

scales, the philosophy has been extended to other

applications as mentioned below.

1. Prepackaging scales are to be marked "For Prepackaging Use Only" or with a similar statement. Yes No N/A

Weight classifying scales are to be marked "For

Rate Determinations Only" or with a similar statement. Yes No N/A

Digital scales indicating in ounces (division size of

not more than 0.1 oz, preferably 0.05 oz) are to be

marked "For Meal Portions Only" or with a similar

statement. Yes No N/A

Livestock, Vehicle, and Railway Track Scales

Code References S.6.3. CA 3011.6.3

The section capacity of a livestock, vehicle, and

railway track scale must be marked on or adjacent

to the identification badge on the indicating element. Yes No N/A

14
Comp! i es? Marking Requirements - Weighing Elements

Code References S.6.4. CA 3001.1.

Weighing elements not permanently attached to an indicating element must be clearly and permanently

marked with:

(a) The name, initials, or trademark of the

manufacturer. Yes No N/A

(b) The manufacturer ' s designation that positively

identifies the pattern or design Yes No N/A

(c) The nominal capacity of the weighing element. Yes No N/A

Note 1: To be permanent, the badge should be a metal

or plastic plate that is riveted, welded, or attached by an adhesive so that a tool is

required to remove the badge. Bolts or screws are not acceptable. Because of the

potential for damage to a badge, a foil

badge is not acceptable.

The badge may be mounted on protected

surfaces such as the side of the weighing

element behind a ramp or under a cover

plate. Access to the badge should be

available with a minimum amount of effort.

Note 2: Small capacity weighing elements may be

marked with a capacity that is greater

than the indicator is capable of displaying. This may occur with an ECR with

a 25 lb display capacity and a weighing

element rated at 30 lb. This is acceptable but the weights and measures official

may conduct a shift test using a test load

of one-half the rated capacity of the weighing element. For example, this would be

15 lb.

General Code Requirements

Identification

Code References G-S.l. CA 3001.1. Complies?

All equipment except weights is required to be

marked on an exterior surface visible after

installation with the following information:

15
C omplies ?

(a) Is the badge visible after installation?

(See note 1

)

Yes No N/A

(b) Is the badge permanent? (See note 2) Yes No N/A

(c) The name, initials, or trademark of the

manufacturer. Yes No N/A

(d) The manufacturer's designation that

positively identifies the pattern or design. Yes No N/A

(e) A nonrepetitive serial number. Yes No N/A

Note 1: Equipment is to be marked on a surface

that is visible after installation in a normal manner. The bottom of a device

(or the back if it is wall mounted) is

not an acceptable surface. The back of

a device is acceptable if it is portable.

Portable is defined as weighing less than

35 lb and having a length and width of

24" x 18" or less.

Note 2: The badge must be permanent. It may be

a metal or plastic plate attached with

pop rivets or adhesive or other means. Removable bolts or screws are not

permitted. A foil badge may be used

provided it is destroyed in any attempt

to remove the badge. Additionally, the

printing on a foil badge must be easily

read and not easily obliterated by rubbing

with a relatively soft object (i.e., wood

of a pencil )

.

Note 3: Remote weight displays have not been

required to have serial numbers because

they typically do not have any electronics

used in analysing the weight signal

received from the weighing element. The

remote display is required to have the

manufacturer ' s name or trademark and model

designation. Similarly, the various "slave"

modules in a modular point-of-sale system;

e.g., printer, keyboard module, and cash

drawer have not been required to have a serial number because they do not have any

"intelligence".. Only the electronics modules

which control the "slave" modules have been

marked with a serial number. This is con- sidered satisfactory and in compliance with

Handbook 44.

16
Facilitation of Fraud

Code Reference G-S.2., G-S .5.1, CA 3001.2., 3001.5.1.,

Power Interruptions Comp! ies?

After a momentary (maximum of ten seconds) power interruption, an indicating element should either return to

zero, display the weight value that was displayed before

the power failure assuming the load has not changed, or display an error signal or meaningless information

which cannot be interpreted as a weight value and which

requires operator intervention to return the scale to

operation. The meaningless information may be , EEE, 6CE1 etc. If the scale returns to an incorrect

weight value, that is a weight value different by more

than one division from the weight value displayed

before the power interruption, the device is considered

to facilitate fraud.

Test method; If the scale is equipped with AZSM (zero

tracking), track off several divisions of weight.

Place a load on the scale and note the weight that is

displayed. Simulate a power failure by pulling the

power plug. Do not interrupt the power for more than

ten seconds. Return power to the device and record

below the manner in which the scale returns to operation.

Repeat the test by using the power switch to interrupt

the power.

Record the method used to return the scale to operation.

Power Plug

1 , Device returns to zero Yes No N/A

2. Returns to the previously displayed

weight value Yes No N/A

3, Displays a meaningless display or error signal which requires operator

intervention. Yes No N/A

4. Displays an incorrect weight value Does not

comply

N/A

Power Swi tch

1 . Device returns to zero Yes No N/A

2, Returns to the previously displayed

weight value Yes No N/A

3. Displays a meaningless display or error signal which requires operator

intervention. Yes No N/A

4. Displays an incorrect weight value Does not N/A

comply

17
Facilitation of Fraud - Tare Operation

Code References G-S.2., G-S - 5.1., G-S.5.2.2.,

G-S.5.6. , CA 3001.2, 3001.5.1

Indicate the type of tare capability available: Complies?

No tare capability ) J Pushbutton tare | |

Keyboard tare | ) Digital tare I t

Thumbwheel tare 1 1

1. Devices equipped with a tare capability, except for

electronic cash registers, are required to provide a clear indication that a tare value has been entered.

If the tare value can be cleared when a load is on the

platform, a clear indication that the tare value has

been eliminated must be provided. Several options

exist to comply with this requirement. The primary

purpose of this requirement is that devices which do

not provide GROSS and NET indications must provide

a lighted legend or annunciator such as TARE ENTERED

or similar statement to indicate a tare value has been

entered.

At least one of the following methods must be used to

indicate a tare value has been entered. Indicate which

method is used.

(a) A separate continuous display of tare is provided. Yes No N/A

(b) The device can display the GROSS, TARE, and NET

weight with proper display identification of this

information. Yes No N/A

(c) The device can display the GROSS and NET weight

with proper display identification of this

information. Yes No N/A

(d) The display indicates only the net weight and a NET legend or annunciator appears when a tare

weight is entered. Yes No N/A

(e) A lighted legend or annunciator of TARE ENTERED

or similar statement is used to indicate that a tare

value has been entered and the display indicates

the net weight. Yes No N/A

(f) An entry of zero should not activate the TARE

ENTERED annunciator. Yes No N/A

18
Complies?

2. If a device is equipped with push button tare and keyboard tare, the entry of either tare value must automatically clear any previous tare entry; i.e., they

cannot be additive. Yes No N/A

The tare value plus the net weight must always equal

the gross weight. Yes No N/A

Recorded Representations of Gross, Tare, and Net Weight

There are two primary considerations concerning the

printing of gross, tare, and net weight values.

First, the recorded values of the gross, tare, and

net weight must be mathematically correct; that is,

gross weight = net weight + tare weight.

Secondly, the recorded values must agree with the

indicated values. If these requirements cannot be

met, a printer cannot be used with the indicating

el ement.

(a) Is the tare weight entry

displayed scale division

kilograms?

consistent with the

in both pounds and

Yes No N/A

(b) If no, the device is not

with a printer.

permitted to interface

Yes No N/A

Push Button Tare

1. If a device is equipped with an external push button

zero; i.e., it does not require a tool to activate

the tare operation, and the device is to be used in

direct sales, then the push button tare must have a motion detection capability of meeting S.2.1.2.

requirements. Yes No N/A

2. If the device has a gross/net switch, the push button

tare must be inhibited when the gross weight is being

displayed. Yes No N/A

3. If the device has a gross/tare/net switch, the push

button tare must be inhibited when the gross weight

is being displayed. Yes No N/A

19
Complies?

4. (a) Does push button tare operate to the full capacity

of the scale?

Yes 1 1 No I I

(b) If no, the push button tare must be inhibited when

the gross weight exceeds the tare capability.

Example: If the scale can only take 9.99 lb as tare, when a gross load of 10.00 lb is placed on the scale, no tare should be taken when the tare

key is pressed. Yes No N/A

For information purposes, test if the push button tare

value is taken to a weight value smaller than the

displayed scale division.

Test method: Apply a load to the scale so that the scale

indication is on the high side of the displayed weight

division but below the zone of uncertainty. It probably

will be necessary to use weights of less than one scale

division to achieve this condi ton. Take this weight as tare by pressing the push button tare key. Test if the

net weight zero reference point is in the center of the

displayed net zero indication. If it is, the scale takes

tare to a value smaller than the displayed tare division.

If the net zero reference point is still on the hgih side

of the net zero division, tare is taken to the displayed

scale division.

Tare is taken to a value smaller than the displayed

scale division I I

Tare is taken to the displayed scale division | | Keyboard Tare

Keyboard tare should be operable only with no load on the platform unless there is a separate display of tare

values or the tare values are recallable and verifiable.

1. One of the following conditions must be met for

keyboard tare entries:

(a) The device has a tare display entirely separate

from the weight display which continuously indicates

the entered tare weight. Yes No N/A

(b) The device has a selectable tare display mode

activated by key or switch and

(i) tare values may be entered only when the tare

mode is selected or Yes No N/A

(ii) tare values may be recalled and verified at

any time Yes No N/A

(c) Entries are permitted only when there is no load

on the platform Yes No N/A

20
Compl i es?

(d) The device indicates gross weight only with the

tare or net weights appearing on a printed weight

ticket. Yes No N/A

Note: Under items (a), (b), and (d), the tare value may

be entered when a load is on the scale platform.

Are keyboard tare value entries consistent with the

displayed scale division in both pounds and kilograms?

Yes No N/A

If NO then one of the following conditions must be met.

(a) A tare value that is not consistent with the

displayed scale division is automatically rejected. Yes No N/A

(b) The tare weight entry must be rounded to the

nearest displayable scale division. Yes No N/A

(c) (i) A tare value entered and displayed in values

less than the value of a displayed scale

division, the tare value must actually be taken

to the smaller weight unit; i.e., the tare

value must be valid. Yes No N/A

(ii) The number of tare divisions must not exceed

20 000. Yes No N/A

(iii) The value of the tare division must be equal

to 1/2 or 1/5 the value of the displayed scale

division. Yes No N/A

Test method: To test if the tare value is taken

to a value smaller than the displayed scale division,

first place a load on the scale that results in a stable display of a weight value. Next, increase

the tare value in the smallest tare increments until

the net weight display just enters the zone of

uncertainty. If the zone of uncertainty is smaller

than the smallest tare increment, increase the tare

value until the displayed net weight changes to the

next lower number. At this point increase the load

on the scale by a fraction of a division, for

example 0.3 d(j or 0.6dd. This should result in a stable net weight display. Increase the tare value

in increments of the smallest tare value. If the

smaller tare values are meaningful, the additional

tare required to reach the zone of uncertainty or breakover point should equal the additonal load

appl ied to the seal e.

(d) If tare is taken to a value smaller than the displayed

scale division, the net weight must be indicated in

values consistent with the displayed scale division

for the gross weight: e. g. if the scale capacity is

100 000 x 20 lb and the tare entry is 10 lb, the net

weight must still be displayed to the nearest 20 lb

division.

21

Yes No N/A
Compl ies?

Digital Tare

Digital tare is the capability that each time the

digital tare key is pressed, one displayed scale

division is taken as tare.

1. The digital tare division must equal the displayed

scale division. Yes No N/A

(a) The digital tare entry may automatically

any previous tare entry or clear

Yes No N/A

(b) Digital tare may add to a push button or board tare entrykeyYes No N/A

Digital tare entries are permitted only under

conditions described in Keyboard Tare item 1.

the

Yes No N/A

Which condition is met?

(Circle) a b(i) b ( i i ) c d

Thumbwheel Tare

There are several considerations applicable to the use of thumbwheel tare on a digital indicating

element. First, if numbered thumbwheels are used

to set a tare value, it is presumed that the

thumbwheel value is the tare display. In this case the indicator is assumed to have gross and

net weight display modes. It is conceivable that

the indicator displays only the net weight but the

following discussion will assume gross and net

weight display capabilities. Possible variations

considered are whether a printer is used, whether

or not a pound/kilogram conversion capability is

provided and the requirements applicable if the

pound/kilogram conversion capability is internally

or externally available. The mathematical agreement

of the gross, tare, and net weight is of primary

importance.

I. Indicator equipped with thumbwheel tare but no Ib/kg conversion.

Condition 1 or 2 must be met.

1. The tare division is consistent with the displayed

scale division. Yes No N/A

If yes, the indicator may be interfaced with a printer for direct sales.

22
Note:

Compl ies?

If the display has a fixed zero, the thumbwheel indication must also have a fixed zero. The fixed zero may be silk screened adjacent

to the thumbwheel provided it has the same

size and spacing as the thumbwheel digits.

2. (a) The tare weight is taken to values smaller than

the displayed scale division.

If yes, this device is not permitted to interface

with a printer for direct sales.

(b) If yes, then the following conditions must be met.

(i) The tare value must actually be taken to the

smaller weight unit;i.e., the tare value must

be valid. (See the test method under Keyboard

Tare i tern 2(c) .

)

(ii) The number of tare divisions must not exceed

20 000 .

(iii) The value of the tare division must be equal

to 1/2 or 1/5 the value of the displayed scale

division.

(iiii) The net weight must be indicated in values

consistent with the displayed scale division

for the gross weight (See example in Keyboard

Tare item 2(d) .

)

Indicator equipped with thumbwheel tare and an internal

Ib/kg conversion switch

Condition 1 or 2 must be met.

1. The tare division is consistent with the displayed

scale division and the thumbwheel division size

must be physically changed when the display units are changed to maintain the consistent division size.

If yes, the indicator may be interfaced with a printerfor direct sales.

2. (a) The tare weight is taken to values smaller than

the displayed scale division.

If yes, this device is not permitted to interface with a printer for direct sales.

(b) If yes, then the conditions of Thumbwheel Tare

item 1.2. must be met.

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

23
Complies?

III. Indicator equipped with thumbwheel tare and an external

lb/kg conversion switch

It is not possible to have numbered thumbwheels which

are consistent with the displayed scale division in both

pounds and kilograms because under G-S.5.3.1. Dual

Indications, comparable weight values for the division

size must be used. Consequently, recorded weight values

cannot meet the two requirements of agreeing with the

displayed weight values, and the gross, tare, and net

weights being in mathematical agreement when numbered

thumbwheels are used. The reason for this is that the

net weight must be indicated to the displayed scale

division used in the gross weight mode. Due to the

inability to meet these requirements when numbered

thumbwheels are used, a printer cannot be used with

an indicating element using this technology.

Since it is frequently desirable to have a printed

record of transactions, a printer can be interfaced

with an indicator with an external pound/kilogram

conversion switch if the thumbwheels (or dial wheels)

are not numbered. If thumbwheels without numbers are

used, several conditions must be met. The conditions

result from G-S.5.1. and G-S.2. The conditions are listed for two types of indicators; (1) those with the

ability to indicate gross, tare, and net weight by

selecting the proper display mode and (2) those

indicators that can display the gross and net weight.

A. Indicators with gross, tare, net display capability.

1. No numbers should appear on the thumbwheels

(or dials). Yes No N/A

2. Tare entries are accepted or updated only when

the thumbwheel position is changed when the

tare weight is being displayed . If the position

of the thumbwheel is changed when the indicator

is in the gross or net display mode, the tare

value should not change. It is acceptable to

automatically switch to the tare display mode

when the position of a thumbwheel is changed

if all switch settings and annunciators convey

correct information. It is the change in thumbwheel position when the tare weight is displayed

that activates the update of the tare value, not

merely the display of the tare value. Yes No N/A

24
Complies?

3. When the weight units are changed by using the

external Ib/kg conversion switch, the tare value

must be converted to the comparable value in the

selected units; e.g., 10 000 lb (dj = 20 lb) becomes

4 540 kg (d^ = 10 kg). The tare value should update

to the actual switch position numbers when a thumbwheel position is changed when the tare value is

being displayed. Yes No N/A

4. The tare weight division is consistent with

displayed scale division.

the

Yes No N/A

Indicators with gross/net display capability.

1. No numbers should appear on the thumbwheels

dials).

(or

Yes No N/A

2. Tare entries are accepted or updated only when the

net weight is displayed and the gross load is zero

so the tare weight can be verified. The tare weight

value will appear as a negative net weight. If the

position of the thumbwheel is changed when the

indicator is in the gross weight display mode or when the scale is under a load, the tare value

should not change. If the gross load is zero and

the display is indicating the gross weight, it is

acceptable for the display mode to automatically

switch to the net display mode when a thumbwheel

position is changed. It is the change of the

thumbwheel position when the gross load is zero

and the net weight is displayed that activates the

update of the tare value, not merely the display

of the tare as a negative net weight. Yes No N/A

3. When the weight units are changed by using the

external Ib/kg conversion switch, the tare value

must be converted to the comparable value in the

selected units; e.g., 10 000 lb (dj = 20 lb) becomes

4 540 kg (d<j = 10 kg). The tare value should update

to the actual switch position numbers when a thumbwheel position is changed when the gross load is zero and the tare weight is being displayed as a negative net weight. Yes No N/A

The tare weight division is consistent with the

displayed scale division. Yes No N/A

25
Facilitation of Fraud - General Considerations

Code References G-S.2., CA 3001.2

Complies?

1. Printers must be automatically inhibited when the

following information is being displayed by the

indicator:

a. Dead-load verification values Yes No N/A

b. R-calibrated values and other test values Yes No N/A

c. Electronic display verification sequences Yes No N/A

2. Manipulation of the power cord or printer cable must

not influence the indicated or recorded weight values. Yes No N/A

3. Operation of associated or non-associated electronic

equipment must not affect digital indications. Yes No N/A

4. Use of any operational functions or options should

not facilitate fraud. Yes No N/A

5. Does the equipment, through its characteri sties and

design, prevent fraudulent operation or inaccurate

weight values. Yes No N/A

Permanence-Materials, Design, and Construction

Code References G-S.3., CA 3001.3

Do the materials, design, and construction make it

probable that:

1 . Accuracy will be maintained? Yes No N/A

2. Operating components will function as intended? Yes No N/A

3. Adjustments will remain permanent? Yes No N/A

Interchange or Reversal of Parts

Code References G-S.4., CA 3001.4

Are parts that may be interchanged or reversed in normal

field assembly:

1 . Constructed so that reversal will not affect

performance? or Yes Mo N/A

2. Marked to indicate proper position. Yes No N/A

26
Indicating and Recording Elements - General

1 .

Code References G-S.5.1., CA 3001.5.1.

The minimum divisions of both indicating and recording

elements must be in values of 1, 2, or 5 times 10n where

n is an integer; e.g. , 0.1, 0.2, or 0.5; 1, 2, or 5; 10,

20, or 50;etc.

Complies?

Yes No IM/A

2. A push button zero may operate in the gross, net, or

tare display mode if the gross load is rezeroed and

all other indications change to the proper value with

respect to the new gross weight zero reference point.

3. A fixed zero cannot appear after a decimal point; i.e.,

all decades after a decimal point must be active.

4. A printer must record the same number of decimal

places as indicated in the display. Example: A

digital indicator may display weight values to

0.01 lb and 0.005 kg. The printer must record a weight value in pounds to 0.01 lb; not to 0.010 lb.

5. The optional center of zero light must be inhibited

at all displayed weight values other than zero.

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

6.

Upon return to gross load zero, a device may automatically display other information*, for example,

it may cycle the time, date, and zero indications,

provided that the display of the other information

occurs only when the scale is at zero, the zero indication can be displayed, or is displayed as part

of the cycled information. The values must be clearly

defined. The scale must display weight values or give an out of balance indication whenever the scale

is out of zero balance. The scale must immediately

indicate weight values when a load is applied to the

scale. Yes No N/A

7.

Computing scales that automatically clear the tare

value after a weighing must require a minimum net

load of 20 dd before the tare value will automatically be cleared. Yes No N/A

Note: This is to prevent the tare weight from

being cleared when the tare is removed from

the scale to be filled. It also prevents

accidental clearing of tare if the net

weight goes slightly positive as the operator

removes the tare from the scale. The minimum

net load of 20 dj is taken from the 0IML

minimum load for Class III scales.

27
Compl ies?

3. Non-weighed item information must be automatically

cleared from the display following computation of

the transaction total. Yes No N/A

4. The addition of tax charges to the transaction total

should not increase the "item" count or display. Yes No N/A

Computing Scales that Display Retail Price Information

After Load Removal

For digital price computing scales that retain and display

accumulated price information following removal of the load:

1 . Accumulated price information may be held following

removal for 15.0 seconds or less. Yes No N/A

2. The computing scale must automatically return to its zero reference. Yes No N/A

3. The computing scale must automatically return to a "non-hold" or active mode at any time a new unit-price

is entered during a "hold" period. Yes No N/A

4. It is acceptable for the scale to initiate label printing during stable loaded platform conditions. Yes No N/A

5. If the scale initiates label printing or "print command"

during the "hold" period, it must automatically return

to an active mode and print the correct weight and

price information for the new load conditions. Yes No N/A

Menu Service Scales

The weight units may be in ounces.

1 . The scale division must be less than or equal to 0.1 oz.

(A scale division of 0.05 oz is preferred.) Yes No N/A

2. If the weight unit is ounces, the scale must be marked

"For Menu Service Only" or with a similar suitable

statement. Yes No N/A

Are all indicating and recording elements appropriate

in design and adequate in amount? Yes No N/A

Are primary indications and recorded representations

clear, definite, and accurate? Yes No N/A

28
Digital Indication and Representation

Code References G-S.5.2.2., CA 3001.5.2.2.

Compli es?

1. Are digital elements designed so that:

a. All digital values of like value in a system agree

with one another? Yes No N/A

Any digital value coincides

analog value?

with its associated

Yes No N/A

All digital values round to

division?

the nearest minimum

Yes Mo M/A

2. a. Does the digital display utilize partial or "half"

segments in the most significant decade (MSD)?

Yes | 1 No | |

h. If yes, the device is required to meet one of the

following two conditions

(i) Blank the complete display when the digit "1"

would appear in the MSD when the minus sign

is also being displayed.

(ii) The minus sign must be masked to provide

separation between the and the digit "1"

in the MSD.

Computing Scales with Multiple Sales

Accumulation Capability

Note: Computing scales which have both the multiple

sales accumulation capability and price-look-up

capability will be considered to be electronic

cash registers. They will be expected to meet

all the requirements applicable to cash registers

and to issue a sales receipt similar to that of a cash register.

For digital price computing scales with the ability to

accumulate multiple weighed and non-weighed item price

transactions:

Yes No N/A

Yes No N/A

1. The scale is required to have an "item" count or "item display" to continuously indicate the number

of items totalized for any transaction. Yes Mo N/A

2. Non-weighed item information must be automatically

prohibited from being entered when the scale is at

any non-zero reference. Yes No N/A

29
Graduations, Indications, and Recorded

Representations - Size and Character

1 .

2 .

1 .

2 .

3.

4.

Code References G- S .5.2.3., CA 3001.5.2.3.

Compl i es?

Are graduations, indications, or recorded representations

uniform in size and character? Yes No N/A

Are subordinate graduations, indications, or recorded

representations appropriately designed or portrayed? Yes No N/A

Graduations, Indications, and Recorded

Representations - Values, Dual Indications

Code References G-S.5.2.4., G-S.5.3.1., CA 3011.5 .2.4.

The lower case "kg" must be used on display panels and

keys when the symbol for kilogram is used. Yes No N/A

The lower case "kg" should be used for printing when

possible. The upper case "KG" is an acceptable symbol

for kilogram if the lower case "kg" cannot be printed. Yes No N/A

Any other metric symbols must comply with the table

given under G-S . 5.6.1

.

Yes No N/A

A printer interfaced with an indicator with an external

lb/kg conversion switch must automatically record the

weight unit in which the indicator is displaying weight

values. Yes Mo N/A

Note: Preprinted weight tickets stating the weight

unit are acceptable for indicators capable

of displaying only one weight unit or which

have an internal Ib/kg conversion switch.

5. An indicator with an external lb/kg conversion

switch must identify the units in which the display

is indicating.

a. The unit should appear adjacent and to the

right of the weight display. Yes No N/A

Note: Adjacent means within a distance equal to

the width of the active display.

b. Front panel mounted toggle switches are required

to be adjacent and to the right of the weight

display and must have the unit identified by an LED or other lighted annunciator. (The position

of the toggle switch alone is not considered an adequate identification of the unit in use.) Yes No N/A

30
Comp! ies?

c. Front panel mounted toggle switches must identify

the switch position and function by a lighted

annunciator* e.g., an LED with the silk-screened

legend Gross or Net. Yes No N/A

d. If back-lighted push button type operational controls

are to define the display mode (e.g., net, gross,

lb, kg), these controls are required to be located

adjacent to the weight display with no other controls

between the display and the descriptive keys. Yes Mo N/A

e. When the power switch is also used as a means for

rezeroing the device, it is required to be marked as

(i) Power/Zero or

(ii) On-Off/Zero

6. If the system has an external Ib/kg conversion switch,

the system must indicate and record in comparable values

in pounds and kilograms. Example: 20 lb and 10 kg.

5 lb and 2 kg. Yes No N/A

7. Devices used in direct sales must have only one Ib/kg

selector switch which converts both the weight display

and tare values into comparable weight values. Yes No N/A

8. Are graduations, indications, or recorded representations properly defined by figure, word, or symbol? Yes No N/A

Graduations, Indications, and Recorded

Representations - Permanence

Code References G-S.5.2.5., CA 3001.5.2.5.

Are all graduations, indications, or recorded representations permanent and legible? Yes No N/A

Values of Graduated Intervals or Increments

Code References G-S.5.3., CA 3001.5.3.

Are all graduations, indications, or recorded representations uniform throughout the series?

Repeatability of Indications

Code References G-S.5.4., CA 3001.5.4.

Does the device repeat, within prescribed tolerances, its

indications and recorded representations for:

1. Increasing load tests?

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

31
2 .

Compl ies?

Decreasing load tests? Yes No N/A

Repeatability of indications including zero? Yes No N/A

Shift or section tests? Yes No N/A

(This is not a Handbook 44 requi rement.

)

a. If the power supply voltage can be varied, is

the device accurate when the voltage is 100 V

and 130 V? (The OIML specification is +10%

and -15% of 117 V .

)

Yes | | No | |

b. If no, over what voltage range does the device

operate? (Do not exceed the limits of 100 V and 130 V.

)

V to V

6. One of the following conditions should be met.

a. Does the scale return to zero within the minimum

applicable tolerance after the load is removed? Yes No N/A

b. If no, test the scale for return to zero using

the test method given below. The scale should

return to zero at least 9 out of 10 times. Yes No N/A

Test method: Rezero the scale. Place a load

of approximately one-half scale capacity on the

load receiving element. Leave the load on the

scale for the time used in a normal weighing

operation. Remove the load. The scale should

return to zero (direct reading), not merely

within the applicable minimum tolerance. Reapply

the load several more times in a manner approximately normal use.

Money Values, Mathematical Agreement

Code References G-S.5.5., CA 3001.5.5.

Are all recorded and indicated digital money values in

mathematical agreement with their associated quantity

representations to the nearest one cent? Yes No N/A

32
The following sample calculations are suggested for price

computing scales.

Correctly

Net Weight X Unit Price = Total Price Rounded

0.10 lb $ 0.04 $ 0.0040 $ 0.00

0.10 lb $ 0.05 $ 0.0050 $ 0.00

or

$ 0.01

0.10 lb $ 0.15 $ 0.0150 $ 0.01 or

$ 0.02

0.31 lb $ 0.85 $ 0.2635 $ 0.26

0.31 lb $ 0.89 $ 0.2759 $ 0.28

0.32 lb $ 0.83 $ 0.2656 $ 0.27

0.32 lb $ 0.89 $ 0.2848 $ 0.28

1.51 lb $ 0.07 $ 0.1057 $ 0.11

1.51 lb $ 0.70 $ 1.057 $ 1.06

1.51 lb $ 7.00 $ 10.570 $ 10.57

2.50 lb $ 0.69 $ 1.725 $ 1.72

or

$ 1.73

2.50 lb $79.29 $ 198.225 $ 198.22

or

$ 198.23

2.54 lb $ 0.79 $ 2.0066 $ 2.01

2.54 lb $ 0.86 $ 2.1844 $ 2.18

2.54 lb $ 3.99 $ 10.1346 $ 10.13

2.54 lb $ 4.25 $ 10.7950 $ 10.79

or

$ 10.80

2.54 lb $99.99 $ 253.9746 $ 253.97

12.54 lb $ 2.25 $ 28.2150 $ 28.21 or

$ 28.22

12.54 lb $99.99 $1253.8746 $1253.87

15.03 lb $ 1.83 $ 27.5049 $ 27.50

20.67 lb $ 0.59 $ 12.1953 $ 12.20

24.51 lb $ 0.89 $ 21.8139 $ 21 .81

33
Recorded Representation s

Code References G-S.5.1, G-S.5.6.

CA 3001.5.1, 3001.5.

6

1. Are all recorded values printed in a digital format?

2. Gross weight must equal the net weight plus the tare

weight.

Note: Handbook 44 does not require that a device print

gross, tare, or net weight, but some weighmaster

laws require recording all three weight values.

3. If the indicating element has a memory so that

it is able to weigh incoming vehicles, loaded or empty, store this weight information, weigh the

outbound vehicle, empty or loaded, and compute

the net weight, the net weight must be computed

with the proper sign and the recorded weight

values must be clearly and properly identified.

4. Multiple tare memory registers:

See the appendix for criteria

Magnified Graduations and Indications

Code References G-S.5.7., CA 3001.5.7.

Does the device use optical magnification of the

indications?

Yes | | No

If yes, does the magnified image conform to all appropriate

requirements? Yes No N/A

Marking, Operational Controls,

Indications and Features

Code Reference G-S.6

1. Thumbwheels must be identified. Yes No N/A

Note: Keyboards or keypads do not have to be identified

although the individual operating keys must be

marked; e. g. , 0, 1 , 2, . .

.

,

9

2. Keys or operator controls visible to the customer during

a direct sale should be marked with words or symbols

so the customer can understand the transaction. Yes No N/A

Compl i es?

Yes No N/A

Yes No N/A

Yes No N/A

Yes No ' N/A

34
Complies?

Note: Keys and controls that are visible only to the

operator and for the operator's use only, need

only be marked with symbols that are understood

by the operator or by someone who has been trained

to use the device.

3. All operational controls on the back panel of a device should be identified. Interfacing plugs

for load cell or printer connections and other

plugs are to be identified by words, symbols, or

codes. Yes No M/A

4. All operational controls, indications, and features

including switches, lights, displays, pushbuttons,

and other features, shall be clearly, and definitely

identified. Yes No N/A

Lettering of Markings and Instructions

Code References G-S.7., CA 3001.6

Are a 1 ^required markings and instructions distinct and Yes No N/A

easily readable?

Suitability of Equipment

Code References G- UR .1.1., CA 3004.1.1.

Is the device suitable for service including the elements

of its design, weighing capacity, computing capability,

etc.? Yes No N/A

Selection Requirements - Environment

Code References G-UR .1.2.

Is the equipment suitable for the environment in which it

is intended to be used including:

1. Electromagnetic and radio-frequency interference

generated by electromechanical equipment, portable

hand-held ratio transmitters, citizens band transmitting equipment, etc.? Yes No N/A

Hostile environment including extreme temperature

and moisture conditions? Yes No N/A

35
Installation Requirements

Code References G-UR.2.1., CA 3004.2.1 Comp! ies?

1. Is the device installed in accordance with the Yes No N/A

manufacturer's instructions?

2. Is the device to be installed at a fixed location?

Yes No

3. If yes, is it so installed that neither its operation

no its performance are adversely affected by any

characteristic of the foundation, supports, or any

installation detail: Yes No N/A

Comments

:

36
APPENDIX 8/22/80

Prototype Criteria

Multiple Tare Memory Registers

for Direct and Indirect Sales

The use of mi croprocessors has made it possible for several tare values to be

entered into a digital indicator by keyboard entries or using push-button tare.

The proper operation of an indicator having multiple tare memory registers

depends upon whether the indicator is used in direct or indirect sales and

whether a printer is used in these situations. In normal circumstances

the indicator will be able to indicate the gross, tare, and net values. A

distinction will be made between tare entries during normal weighing operations and tare values that are entered in a separate programming operation.

I Direct Sale -- No Printer - Tare Entries in Normal Weighing Operation

1. The tare values are to be entered only when the display is in the tare

display mode so the entries can be verified. The display may automatically return to the gross or net mode after a time delay.

2. Each tare value must be recalled and verified before each weighing so the customer can verify the tare value.

II Direct Sale -- Printer - Tare Entries in Normal Weighing Operation

1. The printer must print the gross, tare, and net values as a continuous

sequence so the values are documented and verifiable. If the gross or tare weight is obtained by weighing the inbound weight of a vehicle,

the inbound weight should also be recorded on the weight ticket at the

time of the inbound weighing.

2. The digital indicator is not required to display the tare weight before

each weighing because the weight ticket documents the transaction.

Ill D irect Sale -- Printer - Preprogrammed Tare

This is applicable to computing scales having preprogrammed tare

incorporated with price look-up capabilities. This feature has not been

observed in any other systems except point-of-sale systems.

1. The tare weights can only be entered when the scale is in a special

programming mode.

2. The scale is not required to display or print the gross or tare weight

provided the net weight is recorded. The rationale for this is that

the weights and measures official can verify the accuracy of the

preprogrammed tare weights during inspections.

IV Direct Sale — No Printer - Preprogrammed Tare

The considerations stated in item III apply.

37
( 2 )

V Indirect Sale -- No Printer - Tare Entries in Normal Weighing Operation

1. The tare values are to be entered only when the display is in the tare

display mode so the entries can be verified. The display may automatically return to the gross or net mode after a time delay.

2. Each tare value must be recalled and verified before being used for

the first time in a series of weighings. Once selected, the tare

weight may be retained and used without reverification for all the

weighings requiring the selected tare weight . The tare weight may be

retained until it is replaced when a new tare value is recalled.

VI Indirect Sale -- Printer - Tare Entries in Normal Weighing Operation

The conditions stated in item V apply. Only the net weight is required

for printing when the weight ticket or label is the basis of the transaction.

VII Indirect Sales -- No Printer - Preprogrammed Tare

Each tare value should be verified before being used for the first time

in a series of weighings. This can be achieved by displaying the tare

value as a negative net weight when the gross load on the scale is zero. Once selected, the tare weight may be retained and used for all

the weighings requiring the selected tare weight. The tare weight

may be retained until it is replaced when a different tare value is

recall ed.

VIII Indirect Sales -- Printer - Preprogrammed Tare

The conditions stated in item VII apply. Only the net weight is

required for printing when the weight ticket or label is the basis of

the transaction.

38
RETAIL MOTOR FUEL DEVICE TEST REPORT

GENERAL INFORMATION

Lab Test |

I Field Test I I 'DATE:

Type Approval Test Number: LOCATION:

SPECIFICATION REQUIREMENTS

Schematics Submitted: Yes

No

MANUFACTURER INFORMATION

Zi

Maintenance Manual

Submitted:

Yes

No

Company Name:

Address :

Phone : ( )

PROTOTYPE DEVICE (S) MODEL NUMBER i

1. Retail Motor Fuel Dispenser | | 1.

2 . Remote Console o 2.

3. Computing Register 3.

4. Ticket/Receipt Printer 4.

'5. 5.

INTERFACE (S) TECHNOLOGY

1 . Remote Console Mechanical c

2. Ticket/Receipt Printer Ci Electronic c

3. Electronic Cash Register Ci Analog Display c

4. Cl Digital Display c

5. Ci Postpay c

Preset Money c

Preset Volume c

39
SYSTEM INFORMATION

1 . Device Configuration;

Single Product I I

Dual Product |

|

Multiple Product |

|

Self Contained Single

Self Contained Dual

Remote Single

Remote Dual

2. Reset:

Manual | | Key l_J

Electric I | Time Delay o

3. Totalizer

:

Mechanical: Volume $ Sales

Electronic: Volume Cl $ Sales

(Mechanical Volume Totalizer Required on Dispensers)

Shift Totals I |

4 . Pulser

:

Mechanical |

|

Electronic |

|

Pulse Rate (Gallon Display) Pulses Per Gallon

Pulse Rate (Liter Display) Pulses Per Gallon I I

Liter |“|

Pulse Rate (Money) Pulses Per Penny

40
5 . Display ;

Segment Check I | Diagnostic Check

Volume:

Minimum Indication

Gallons 0-1 I I -01 I I

Liters .01 |

| .001 I 1

Fixed Decimal |

I

Floating Decimal I I

Selective Decimal I !

Maximum Volume Display Gallons

Liters

Volume Display Suppression;

Gallons None |

I

Liters

Unit Price:

Maximum $ /gallon.

Maximum $ /liter.

Total Sale:

Maximum Display $

6 . Gallon/Liter Conversion:

None I I

Cut Jumper Wire |_ I

Switch Position I I

Metric Gear Box | I

New Chip I I

.001

41
7. Allocation Control:

None I |

Money |

I

Volume | I

8 . Battery Power Back-up:

Yes |~| No |”|

(Required for digital indicating dispensers)

9 . Other Standard Features:

A.

B.

C.

10 . Other Optional Features : A.

B.

C.

11. Definitions:

Allocation Control - A means of setting a dispenser or console for a maximum volume or total sale delivery for rationing purposes.

Electronic Pulser - A pulse transmitter utilizing electronic means

such as light beam interruption to provide pulse counts.

Mechanical Pulser - A pulse transmitter utilizing mechanical means

such as reed switches, gears, and magnets to provide pulse counts.

Fixed Decimal - Decimal point that is fixed and permanently placed,

not intended to be repositioned.

Floating Decimal - Decimal point that shifts its position automatically during the operation of the device, such as shifting from

99.9y9 gallons to 100.00 gallons when volume exceeds 100.00 gallons.

Selective Decimal - Decimal point that can be electronically shifted

by a switch, by cutting a jumper wire, or replacing a jumper wire,

etc.

42
EXAMINATION CHECKLIST

RETAIL MOTOR FUEL DISPENSER

1.14. GENERAL CODE REQUIREMENTS

Spec i f i c at ions * Compliance

Identification. All equipment shall be

clearly and permanently marked (requires

the use of a tool in order to remove) on an exterior surface visible after installation with the following information:

A. Name, initials, or trademark of the

manufacturer.

B. The manufacturer's designation that

positively identifies the pattern

or design.

C. The nonrepe t i t i ve serial number.

Facilitation of Fraud

A. Electronic dispenser - Is the dispenser incapable of accepting or com- puting a unit price change while the

dispenser is "on"?

B. Is correct data retained on dispenser

and transmitted to remote indicators,

if used in conjunction with remote

indicators, under following power

failure/interruption cond it ions?

1. Power f a i lure/ i n t er rup t i on during

deliveries.

2. Power f a i lu re/ i n t er rupt i on between Yes No N/A

t ransac t i ons

.

3. Power fai lure/ interrupt ion between Yes No N/A

delivery and shut-off.

Permanence. Equipment shall be of such

materials, design, and construction as to make it probable that, under normal

service conditions:

A. Accuracy will be maintained. Yes No N/A

B. Operating parts will continue to

function as intended, and

Yes No N/A

C. Adjustments will remain reasonably

permanent

.

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A
1.14. GENERAL CODE 1 KEMENTS

Code Section Specifications Compl i ance

G-S .4 . U. Interchange or reversal of parts. Yes No N/A

G-S .5 .

G-S .3.1 .

5. Indicating and recording elements.

A. Appropriate in design and adequate in

amount

.

1.

Arc* the maximum money and volume Yes No N/A

indications appropriate for its

intended use?

2. If volume indications are sup- Yes No N/A

pressed when dispenser is turned

on, is the suppression less than

0. 009 gallon? How much suppression?

gallon/1 i ter

.

3. If a digital indicator dispenser Yes No N/A

is used in conjunction with a prepay remote console is the

volume displayed on dispenser to

the nearest 0.001 gallon?

a. If a digital indicator dispen- Yes No N/A

ser displays volume to the

nearest 0- 01 gallon and is used

in conjunction with a prepay

remote console, does the dispenser deliver at least the prepaid

dollar amount for all total sales

up to the capacity of the

i nd icators?

Unit Price vs. Preset Examples:

UNIT

PRICE

PRESET

$

SHOULD

$

DELIVER

VOL

1.319 8.00 8.01 6.07

1.319 14.00 14.01 10.62

1.419 5.00 5.01 3.53

1 . 169 10.00 10.01 8.56

44
1.14. GENERAL CODE REQUIREMENTS

Code Section Specifications Compl i ance

b. If a digital indicator dispen- Yes No N/A

ser displays volume to the

nearest 0.01 gallon, is there

mathematical agreement at all

volumes and unit prices?

Mathemat i cal Agreement Example

:

UNIT INDICATED TOTAL SALE

PRICE X VOLUME = ± 1/2 CENT

1.319 X 6.06 = 7.99

1.319 X 6.07 = 8.01

1.319 X 10.61 = 13.99

1.319 X 10.62 = 14.01

1.419 X 3.52 = 4.99

1.419 X 3.53 = 5.01

1.169 X 8.55 = 9.99

1.169 X 8.56 - 10.01

B

.

Clear

,

definite and accurate. Yes, No N/A

C. Easily read under normal operating Yes No N/A

conditions.

G-S.5.2. 6. Graduations, indications and recorded

representations

.

G-S.5.2.1. A. Analog - Designed to advance Yes No N/A

cont inuously

.

G-S.5.2. 2. B. Digital - Test at least

individual deliveries for each mode

(postpay, preset money, preset volume).

1. All like digital money values Yes No N/A

must be in agreement.

2. All like digital volume indications must agree except volume

indications of:

45
1.14. GENERAL CODE REQUIREMENTS

Code Section Spec i f i c a t i ons Cotnpl i ance

G-S.5.2.3.

G-S .5 . 2.4.

a. Dispensers and pos t pay / prepay Yes No N/A

(preset money mode) remote con- soles must agree within

$0,005 4- unit price.

Example: Unit Price = $1. 329/gal.

$0,005 4 $1. 329/gal =0.0038

gal.; rounded off to 0.004 gallon

maximum disagreement between dispenser and remote console.

b. Digital indicating dispensers

used in conjunction with a remote

console in preset volume mode :

1. Must indicate at least the Yes No N/A

volume preset on the console, and

2. Must be in mathematical Yes No N/A

agreeement with total sales

indications + $0,005.

(Volume x Unit Price = Total

Sales +_ $0 . 005 . )

3. Totalizers. On several individual Yes No N/A

deliveries, check the accuracy and

ageement of the dispenser mechanical

totalizer with the dispenser and

console digital totalizer displays.

4.

Digital values agree with asso- Yes No N/A

ciated analog value to the

nearest minimum graduation.

C. Size and Character.

D.

1 . Uniform in size and character. Yes No N/A

2. Subordinate graduations, indi- Yes No N/A

cations, and recorded representations appropriately portrayed

or designated.

Values adequately defined. Yes No N/A

46
Code Sect

G-S ,5.2.5

G-S.5.3.

G-S. 5. A.

G-S. 5. 5.

G-S. 5. 7.

G-S. 5. 8.*

G-S .6.

1.1 A . GENERAL CODE REQUIREMENTS

.on Spec ifications Compl i ance

E. Permanence. All graduations, indica- Yes No N/A

tions, or recorded reprcsont.il i nns must be permanent and legible.

7. Values of graduated intervals or incre- Yes No N/A

ments. Uniform throughout any series.

8. Repea t ab i 1 i t y o f ind i c a t i ons . Yes No N/A

9. Money values, mathematical agreement. Any

recorded money value and any digital money

value indication must be in mathematical

agreement with its associated quantity

(volume) representation or indication to

the nearest one cent.

FORMULA: Unit Price X Indicated

Volume = Total Sale +^1/2 Cent

Check mathematical agreement under following conditions:

A. At various flow rates, including

maximum and minimum.

B. Snapping nozzle on and off several

times during delivery.

C. At several unit prices including low

price and maximum pricing capability

of computer.

D. Turn dispenser off during delivery

with nozzle open.

10. Magnified graduations and indications.

Conform to all requirements for graduations and indications.

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

11. Agreement of indications. Analog indica- Yes No N/A

tions intended to indicate the same amount of volume shall not differ by

more than the acceptance tolerance of the

de v i ce

.

12. Marking, operational controls, indica- Yes No N/A

tionsj and features shall be clearly and

definitely identified.

47
1.14. GENERAL CODE REQUIREMENTS

Code Section Spec i f icat i ons • Comp 1 i ance

C-S .7 .

G-UR. 1 .

1

G-UR-1.2.

G-UR. 2.1.

13. Lettering. Required markings and Yes No N/A

instructions shall be permanent, distinct

and easily read.

14. Suitability of equipment for intended Yes No N/A

service with respect to elements of its

design.

15. Environment. Suitable lor environment of Yes No N/A

its intended use, including hostile

weather and radio frequency interference.

16. Installation.

A. Installed in accordance with manufacturer's instructions.

Yes No N/A

B. Performance not adversely affected

by any detail of the installation.

Yes No N/A

G-UR. 2 . 1 .

1

C. Identification and all required

markings readily observable.

Yes No N/A

G

- UR .2.3. 17 . Accessibility for testing purposes. Yes No N/A

G-UR. 3. 3. 18. Position of equipment. A device equipped Yes No N/A

with a primary indicating element shall

be positioned so the indications may be

accurately read and the measuring operation observed from some reasonable "customer" position. (Driver's position

inside vehicle being fueled and attendant's position during fueling.)

G-UR. 3. 4. 19. Responsibility. Money-operated (coins,

tokens, dollar bills) devices shall have

the following information clearly and

conspicuously displayed:

A. The method for return of monies paid Yes No N/A

when the product or service cannot

be obtained.

B. Name, address and phone number of the

local servicing agent for the device.

Yes No N/A

48
3.30. LIQUID-MEASURING DEVICE CODE REQUIREMENTS

Code Sect

S. I

.

5.1.1.

5. 1.1.1.

S.1.1. 2.1

5.1.1. 3.

5.1.1. 4.

S . 1 . 2 . 1

.

S. 1 .2 .2 .

l on Spec i. f icat i ons Cornpl i ance

20. Design of indicating and recording elements and of recorded representations.

A. Primary elements.

1. The device shall be equipped with Yes No tt/A

a primary indicating element and

may also be equipped with a primary recording element.

2. The device shall indicate, and Yes No N/A

record if equipped to record, its

deliveries in terms of liters or gallons and decimal or fractional

equivalents.

3. Value of smallest unit of indi- Yes No N/A

cated delivery shall not exceed

the equivalent of one pint.

4. Advancement of indicating and

recording elements.

a. Shall be susceptible of Yes No N/A

advancement only by the mechanical operation of the device

(except for clearing the device

to zero).

b. May be cleared by advancing Yes No N/A

to zero if the advancing movement cannot be stopped until

zero is reached, or in the case

of indicating elements only,

the elements are automatically

obscured until the elements

reach the correct zero condition.

B. Graduations length. Varied so that Yes No N/A

they may be conveniently read.

C. Graduations width.

1. 0.008 inch or more wide. Yes No N/A

49
3.30. LIQUID-MEASURING DEVICE CODE REQUIREMENTS

Code Section Spec i f i cat ions Compliance

2. In any series of graduations, the Yes No N/A

graduation width shall be not

greater than the width of the

minimum clear interval between

graduat ions

.

3. Main graduations shall be no more Yes No N/A

than 50 percent wi der than subordinate graduations.

5. 1.2.3. D. Clear interval between graduations - Yes No N/A

No less than 0.04 inch.

5.1.3. E. Indicators.

S. 1.3.1.

S.1.3. 2.

S.1.3. 3.

1.

Symmetry - Index shall be sym- Yes No N/A

metrical with respect to its

associated graduations.

2 . Length

.

a. The index shall reach to the Yes No N/A.

finest graduations; or

b. If the indicator and gradua- Yes No N/A

tions are in the same plane,

the distance between the indicator end and the ends of

the graduations shall be no more than 0.04 inch.

3. Width.

a. Not greater than the width of Yes No N/A

the widest graduation and the

width of the minimum clear

interval between graduations.

b. That portion of the index Yes No N/A

that may be brought into coincidence with the graduation

shall be of the same width

throughout the length of the

index that coincides with the

graduat ion

.

50
3.30. LIQUID-MEASURING DEVICE CODE REQU I REMENT S

Code Section Specifications Compliance

S.l.3.4. 4. Clearance - Between the index and

the graduations shall be no more

than 0.06 i nch

.

Yes No N/A

S. 1.3.5. 5. Parallax - Reduced to practicable

min imurn.

Yes No N/A

S. 1.4.1. F. Indication of delivery. Shall show

automatically its initial zero con- dition and amount delivered up to

nominal capacity of the device.

Yes No N/A

S.l.4.2. G. Return to zero. Yes No N/A

S.l.4.3. H. Display of unit price and product

ident i ty

.

Yes No N/A

S.l.4.4. 1. Money-Value computations.

1. Full-computing type. Yes No N/A

S.l.4.4. 2. Analog money value indications Yes No N/A

shall not differ from the mathematically computed money value

(Quantity x Unit Price = Sales Price),

for any delivered quantity, by an amount greater than one-half the value

of the money value division.

S. 1.4. 4.1. 3. Money-Value divisions analog Yes No N/A

shall be as follows:

a. Not more than 1 cent at all

unit prices up to and

i nc lud i ng $ 1 . 00

.

b. Not more than 2 cents at all

unit prices greater than $1.00

up to and including $3.00.

c. Not more than 5 cents at all

unit prices greater than S3. 00.

S. 1.4. 4. 2. 4. Money-Value Divisions, Digital. Yes No N/A

A computing type device with digital indications shall comply with

the requirements of paragraph G-S.5.5.

Money values, mathematical agreement,

51
3.30, LIQUID-MEASURING DEV 1C K COOL REQUIREMENTS

Code Section Spec i f icat i ons Con: pi i anc

e

S.l.4.5.

S . 2 .

5.2.1.

5.2.2.

5.2.3.

S. 2 .4 .

and the total price computation shall

be based pn quantities not exceed inp,

0.01 gallon intervals for devices

indicating in inch-pound units and

0.02 liter for devices indicating in

metric units.

J. Travel of indicator on lubricant Yes No N/A

devices. The relative movement of

the indicator and graduations shall

be not less than one inch per one

pint of delivery.

21. Design of measuring elements.

A. Vapor elimination - Automatic vapor/air Yes No N/A

eliminator with vent lines made of

metal tubing or other suitable rigid

mat er i a 1

.

B. Provision for sealing any measurement Yes No N/A

element and adjusting mechanism.

C. Directional flow valves shall be Yes No N/A

automatic in operation.

D. Stop mechanism.

1. Position secure from impact or Yes No N/A

direct pressure.

2. Adjustable to provide for deli- Yes No N/A

veries within prescribed

tolerances

.

3. If two or more stops may operate

selectively to permit deliveries

of predetermi ned amounts

:

a

.

The position for the proper Yes No N/A

setting shall

defined.

be accurately

b. Inadvertent displacement from

position shall be obstructed.

Yes No N/A

c

.

The deliverv for which the Yes No N/A

device is set shall be con- spicumislv indicated.

52
3.30. LI QU 1 D-MKASU K J NC DEVICE CODE RKQUIKEMKNTS

Code Section Specificat ions

S .2.5.1.*

S.2.7 .1.

S.3.

S.3.I.*

S.3.5.

E. Zero-set-back interlock.

1. After device is turned off, prevents subsequent delivery until

indicators have returned to their

correct zero positions.

2. Starting lever shall be in shut

off position and zero- set-back

interlock engaged before nozzle

can be returned to its designed

hanging position, or what appears

to be its intended hanging position from a reasonable customer

position.

3. Where more than one dispenser is

connected to single pump there

shall be an automatic control

valve which prevents fuel from

being delivered until the indicating elements have been returned

to their correct zero position and

engaged

.

E. For lubricant devices only, other

than meter types, it shall become

inoperable or give a conspicuous

and distinct warning when the level

of lubricant becomes so low as to

endanger the accuracy of measurement.

22. Design of discharge lines and discharge

line valves.

A. Diversion of measured liquid. No

means shall be provided to allow any

measured liquid to be diverted from

the measuring chamber or from the

discharge line. (See Code Section

3. 30. S. 3.1.* for discharge outlets

1-1/2 inches or larger, and fueling

trucks.

)

B. Discharge valve may be installed in

the discharge line only if the device

is of the wet-hose type.

Compl i ance

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

Yes No N/A

53
3.30. LIQUID-MEASURING DEVICE CODE REQUIREMENTS

Code Sect

S.3.6.

S . 3 . 7 . *

S.4.1.

UR. 1 . 1

.

UR. 1.1.1.

UR. 2.

UR. 2. 1.

UR. 2. 2.

l on Spec i f i cat ions Compl i ance

C. Antidrain valve. A wet-hose, pres- Yes No N/A

sure-type device shall have an effective antidrain valve incorporated in

the discharge valve or adjacent

thereto.

D. Nozzles for use on retail motor fuel Yes No N/A

devices shall be equipped with an effective antidrain valve.

23. Marking requirements - Limitation of use Yes No N/A

information shall be clearly and permanently stated on the device.

USER REQUIREMENTS

24. Length of discharge hose. No longer Yes No. N/A

than 18 feet (except for marinas and

airports - hose shall be as short as practical, no longer than 50 feet).

25. Installation requirements.

A. Plumb and level Yes No N/A

B. Di scharge rate - Actual maximum d i s- Yes No N/A

charge rate shall not exceed the

rated maximum discharge rate.

54
WEIGHING DEVICE TEST REPORT

ELECTRONIC HOPPER SCALE

This test report does not include indicating and recording devices. These are included in the Weighing Device Test Report - General Information. A complete

system test report for electronic hopper scales includes the appropriate

sections of that report as well as the report below:

Field Test No: Date :

Locat ion:

SPECIFICATION REQUIREMENTS

Schematics Operating

Submitted Yes No Manual Yes No

MANUFACTURER INFORMATION

Company Name:

Address :

Phone :

Company Contact:

PROTOTYPE DEVICE INFORMATION

Model Number :

Capacity :

Minimum Increment:

LOAD CELL DATA

Manufacturer :

Model Number :

Output (mV/V) :

Type of Cell :

Number of Cells:

Maintenance

Manual Yes No

55
HOPPER SCALES - ELECTRONIC

CODE REFERENCE COMPLIANCE

Identification/ Marking

G-S.l

G-UR.2.1.1

1 . Name, initials or trademarks of the manufacturer. Yes No

S.6.4 2. Manufacturer's model designation that positively

identifies the pattern or design. Yes No

3. Non-repet it ive serial number. Yes No

4.- Nominal capacity of scale. Yes No

5. Ident i f feat ion/marking information clearly and

permanently marked. Yes No

6. Identification/marking information must be visible

after installation. Access to badge must be visible

with minimum amount of effort.

Yes No

Note: Item 2 must be a specific model number.

A series number is not acceptable.

(Example: Model 500 not Series 500.)

Note: In Item 5, permanent means metal plate

riveted in place. Foil tags are not

acceptable

Installation and Design of Weighing Elements

G-UR.2.1 1 . Using the engineering drawings, schematics, and

3004.2.1 installation instructions, is the device

installed properly. Yes No

G-UR.1.2 2. Suitability of equipment for the environment in

UR. 2.

which it will normally be used including:

3004.2.3

a. Weather. Yes No

b. Electromagnetic and radio interference. Yes No

c. Protection of load cell cables. Yes No

d. Sealed moisture proof junct ion boxes. Yes No

G-UR.2 .

3. Does the design provide for proper testing of

3004.2.3 the device. Yes No

56
CODE REFERENCE COMPLIANCE

Installation and Design of Weighing Elements

S.1.8 4. Adjustable components:

S.l.4.2 a

.

Held securely in place mechanical. Yes No

S.1.8. b. Calibrating controls or access to such

3011.4.2. controls supplied with provisions for

sealing. Electronic controls only. Yes No

G-S .2 5. Does the equipment prevent fraudulent operation

3001.2 or inaccurate weight values. Yes No

G-S. 3 6

.

Do the materials, design, and construction make

UR. 2 .4 it probable that:

3001.3

a

.

Accuracy will be maintained. Yes No

b. Operating components will function as intended

.

Yes No

c

.

Adjustments will remain permanent. Yes No

Remarks: (Include specifics for any area of

non-compliance in installation and

des ign sec t i on .

)

PERFORMANCE - STATIC

CODE REFERENCE

Increasing Load Test

COMPLIANCE

N.1.1 A. Must be to capacity.

3012.1.1

B. Should utilize certified weight in its entirety.

C. May use weight substitution procedures if

necessary.

D. Will utilize "error weights" for error determination.

Note: When "error" weights are utilized, the

digital tolerance does not apply.

1. Does the scale meet required tolerance. Yes No

57
CODE REFERENCE COMPLIANCE

Decreasing Load Test

N.l .2 1 . Does the scale meet required tolerance. Yes No

3012.1.2

Does the scale meet absolute value of

acceptance tolerance.

Zero Repeatability

N.l. 2.1 1 . Does scale repeat zero within the minimum

tolerance

Yes No

Repeatability of Indications

G-S .5 .4 1 . Does the scale repeat weight indications within Yes No

3001.3.4 absolute value of acceptance tolerance.

58
BULK WEIGHING SYSTEMS AND AUTOMATED BATCH CONTROLLERS

In addition to the applicable separable component tests, ( i . e . , indicator, hopper scale, etc.), bulk weighing systems and controllers shall

have dynamic tests applied as part of their type approval or pattern

approval examination.

The scales utilized in the bulk weighing system must be calibrated as close as possible to zero error by a calibrating service.

Select the closest appropriate scale (vehicle, railway, or industrial),

for checkweighing of the bulk material. Repeatability must be within

one-fourth of tolerance.

Requirements for Checkweighing Scale.

1. Preferably mechanical with a beam and good sensitivity.

2. Repeatable - both zero and test weight indicators.

3. Electronic scales may be used, but error weights should be utilized

to determine true weight indications.

Procedure for Checkweigh Scale Test.

1. Perform section test and note errors.

2. Perform a distributed load test throughout the weight range to be

utilized during the checkweighing operation and note errors.

3. Use the errors found in items 1 and 2 above to construct a correction

chart to be utilized in the checkweighing operation.

Example: Vehicle scale 60' x 10' (A sections): 120,000 lb. capacity.

a. Section errors at 43,000 lbs.

1. +40

2. +40

3. +40

4. +50

b. Distributed load errors with 29,000 lbs.:

on sections l and 2 = +20

on sections 3 and 4 = +25

59
c Distributed load errors with 45,000 lbs.:

on sections 1 and 2 = +40

on sections 3 and 4 = +45

d. Distributed load errors with 75,000 lbs.:

on sections 1, 2 and 3 = +70

on sections 2, 3 and 4 = +75

The error graph obtained from the above example data is given on the

next page. The two errors which will be used in the example below are obtained from the error graphs:

We ight Error

Tare weight of vehicle 23,000 +2 L from graph

Gross weight of vehicle 67,500 +62 from graph

4. Formula for error coinpensat ion during checkweighing

indication - (error value) = true weight.

Example

Truck tare weight indication = 23,000 lbs.

23,000 - (+21) = 22,979

Truck gross weight indication = 67,500 lbs

67,500 - (+62) = 67,438

True net weight = 67,430 - 22,985 = 44,445

67,438 - 22,979 = 44,459

Notes

1. It is recommended that the checkweigh scale be adjusted

and calibrated by a scale service company to bring all errors as close as practical to zero. This may eliminate

the need for an error graph.

2. Scales exhibiting large differences in section errors (even

though within tolerance), or a very non-linear error, should

not be used for checkweighing.

3. Weight trucks intended to be used as a weight standard for error determination or checkweigh scales should have their

weight verified with certified weights via a substitution

comparison prior to the checkweigh scale test.

60
ooooooo —1 ro co cn oi ~-j o

61

ERROR

GRAPH

EXAMPLE

ASSUMED

LINEAR

APPROXIMATION
PROCEDURE FOR CONDUCTING THE DYNAMIC TEST

Sulk Weighing Systems and Hopper Scales .

1. Determine tare weight from checkweigh scale for the receiving

vessel

2. Load system under test with first draft of material.

a. Record weight indication.

b. Print weight if system is equipped with a printer.

3. Discharge mater ial into receiving vessel.

a. Check return to zero.

b. If the indicator does not return to zero, record

the indicated value with appropriate sign.

4. Return receiving vessel to checkweigh scale and determine

gross weight.

a. Compute the net weight based on the checkweigh scale.

5. Compare the checkweigh net weight to the system under test

weight indication.

a. The checkweigh net weight is considered the standard.

6. Compute the percent error between the indicated net and the

standard net weight.

a. Formula for percent error:

Indicated net - Checkweigh Net = Difference

Difference x 100 = % error

Checkweigh Net

Example: Checkweigh Net = 20,000 lbs.

Indicated Net = 20,030 lbs.

20,050 - 20,000 = +50

+50 x 100 = +.25% error

20", 000

7. The maximum permissible error is + 0.30%, number based on tests

conducted in California.

62
8. For bulk weighing systems utilizing multidrafts and a printer:

a. If the individual draft weights are printed, the scale condition

before and after each draft must be printed unless the system

is inhibited from operation with indications other than zero.

b. If the value printed is a net weight for one or more drafts

it must be a true net weight computation.

9. Number of tests to be performed.

a. A minimum of 15 drafts or system cycles should be checkweighed

on each inspection.

10. When performing dynamic tests, all variables such as fuel in trucks,

water in mixer tanks, etc., must be controlled or compensated for.

11. It is important that the receiving vessel (truck, railcar, etc.),

be positioned at the same place on checkweigh scale for both tare

and gross weights. Checkweigh scales should be rechecked after

completion of tests.

12. Sample test data sheet.

(To be attached)

63
NBS

^06*—

Analysis

paper

Truck ID 23 jB 78 *

CT> 00 122 1 1 r” : ot*

CD CL C OO * % DIFF

-0.13 oi

00oo1

-0.77 0.26 i

LB DIFF -37 J

r-LO1 L

-26 [

-250 83 1

C.W. NET

28730 32750 32760

CO

CD

CNJ CO

32093

Batch ZeroReturn o o O+ o

Ticket NET

CO

CDVO

00

CM

CO

CD

VO

CNJ CO

32734

CO

CM

CMCO

32176 i :

Add

Mix

LB o

LO

°°. VO

CD*U ! OCMQT) = _J

CO

CO 1933 1974 CCoo

CM

1749

vehicle 9 i C _l

C\J«£ or id c3

CNJ CO

CM

LIZ 1

LfrZ

O

CM

r

static 1

CMT 2

LB

O

CO

CO

ned

on

a]

CMT 1

LB o

r> &>

CM

O

VO

CO£

3400 oLO

<u

determil i

Agg 5

LB oo

CNJ

2160

03CTt

DTO'

ra

cement

i/eight

as

Agg 3

LB S:

CNJ oo §2

12120

*«- £•r—

CL)

O ^

4->

U

-c cu CD

•r- CJ

CNJCD CC

CD—

cC 1

2640 2720 2680

12160

— s s

ii 1 ii Oil—

ois;

II 3

CJ 1 ! 1

CDCQ CD—

O

CNJ CD

CO

10280 11660 oCNJ

r-*

i^1 1 —

64 ii (,
Automatic printers are being utilized to record the weight

indications in batching plants. The printers receive signals

from a measuring device, which in the past was used only for

proportioning the mixture. Proportioning does not require

such fine weighing accuracy as is necessary for determining

the pay quantity of the resulting product. Testing a device's

accuracy in a stated condition does not necessarily indicate

the accuracy when the batching operation is in progress.

Inadequacies such as gates failing to open all the way can

be determined by dynamic testing.

65
8/22/80

Type Approval Criteria

Permanence Performance Testing

for Scales and Electronic Cash Registers

Measuring devices and components whose accuracy with respect to the applicable

tolerances may change significantly with use over time, are subject to permanence

testing during the type approval process. Permanence testing consists of subjecting a device to actual or simulated use over a period of time and periodically

testing the device for accuracy during that time.

The permanence test may be performed in the laboratory for scales with a capacity

of 500 lb or less. Scales with a capacity greater than 500 lb and other devices

requiring a permanence test will be tested at a field installation where tney

receive routine use. Scales with a capacity greater than 500 lb cannot be

tested in the laboratory because current laboratory equipment cannot handle test

loads of sufficient magnitude for the permanence test. The laboratory test for

scales is defined in the paper titled "Laboratory Permanence Test for Scales."

The procedures for permanence testing at field installations are defined in

separate papers for the various devices subject to field tests.

Examples of the types of devices and components subject to permanence testing are:

1. scales in which the weighing element is permanently attached to the

indicating element, and

2. weighing elements not permanently attached to the indicating element.

Devices and components which do not significantly affect measurement accuracy

will generally not be subject to permanence testing but the device or component

will be subject to an initial field verification test where the device must be

installed in an operating system and must perform properly and within acceptance

tolerances when tested at the time of installation. Examples of these types of

devices or components are:

1. digital indicating elements for scales;

2. electronic cash registers;

3. label or ticket printers, and

4. data processing units which incorporate label or ticket printers.

There are three different sets of field test time and tolerance parameters

under consideration. The three sets represent the minimum acceptable conditions

necessary to fulfill reciprocity requirements between enforcement jurisdictions.

Comments are requested from members of the Task Force on National Typp Approval

weights and measures official s, and industry representatives to aid in selecting

the most acceptable permanence test alternative. It is hoped that the set of

parameters chosen will be applied to all scales subject to a field permanence

test.

66
The three sets of parameters being considered are:

1 . (Current method being applied in California)

The field examination to be conducted at an operating test location will

consist of an initial exam followed by two additional field tests for

permanence a minimum of thirty days apart. The total duration of the test

is normally a minimum of 60 days from the initial test.

The initial set of tests will establish the initial errors on a device.

All errors on these tests must be within the acceptance tolerance.

The results of the second and third field examinations for permanence

must be within maintenance tolerance and, in addition, shall not have

changed by more than the absolute value of the acceptance tolerance from

the initial errors for a particular test load in a given test.

2. The field examination to be conducted at an operating test location will

consist of an initial set of performance tests at the start of the field

permanence tests. A second set of performance tests will be conducted

20-30 days after the initial tests. The results of all tests must be

within acceptance tolerances.

3. The field examination to be conducted at an operating test location will

consist of an initial set of performance tests at the start of the field

permanence test and a second set of performance tests conducted 40-50

days later. The results of the initial tests must be within acceptance

tolerance. The errors as determined in the first set of performance

tests will serve as reference numbers to which the results of the second

set of performance tests will be compared. The second set of performance

tests will be conducted 40-50 days after the start of the field permanence

test. The results of the second test will be compared to the results

of the first test for the corresponding test and test load. The errors must not have changed by more than the absolute value of the acceptance

tolerance applicable to the test.

Notice that the errors may fall into the maintenance tolerance area on the second test but it is also possible that if a device has an initial

test result error on one limit of the acceptance tolerance and the error

shifts to the other limit of acceptance tolerance, the device fails the

test.

67
Type Approval Criteria

Laboratory Permanence Test for Scales

A laboratory permanence test consists of repeatedly applying to the scale a load of between one-quarter and one-half, inclusive, of scale capacity and

periodically testing the scale for accuracy during that time. Normally, a scale which is subject to the laboratory permanence test will not be subject

to any field tests for the purpose of receiving type approval. A field test

may be conducted if the results of the laboratory tests raise questions about

the permanence of the device. Under these conditions the reasons for conducting a field permanence test will be reported to the manufacturer.

The laboratory permanence test may be performed on scales with a capacity of

500 lb or less. The limitation on scale capacity exists because current

laboratory equipment cannot handle the loads required to test larger scales.

The accuracy of the scales under test will be determined by conducting

increasing and decreasing load tests and shift tests. The scales shall be

tested to capacity using known test weights. The scale should be tested to

capacity at a minimum of eight equally spaced points. The minimum decreasing

load test will consist of testing the scale at half-capacity after the scale

has been loaded to capacity.

Because of the ease of testing price computing scales, it is recommended

that the increasing load test for computing scales (approximately 30 lb

capacity) consist of testing the scales at loads of 0.05, 0.1 5, 0.45 , and

0.95 lb and at one pound intervals to one-half capacity and at two-pound

intervals above one-half capacity to capacity. Larger capacity price computing scales should be tested in one-pound intervals to five pounds and in

convenient steps to capacity so a minimum of eight additional points are tested.

These are minimum tests.

The shift tests should be conducted with a load equal to one-half the scale

capacity centered in the quadrants of the scale as designated below (source

is NBS Handbook 112):

Bench or Counter Scales

Equal Arm Scales

68
Other Small Platform Scales

The laboratory permanence test will consist of the following:

1.

Conduct a minimum of two increasing and decreasing load tests and two

shift tests as the start of the permanence test.

2.

Repeatedly apply a load to the scale for a minimum of 100 000 weight

applications. Periodically during this time a minimum of six increasing

and decreasing load tests and six shift tests should be conducted. If the

scale errors vary significantly with respect to the tolerance, more tests

should be performed during the time the load is being applied to the scale.

The load tobe repeatedly appl ied to the scale should be approximately one- half scale capacity for scales with a capacity of 100 lb or less. For scales

with a capacity greater than 100 lb and less than or equal to 500 lb, the

applied load should be between one-quarter and one-half, inclusive, of scale

capaci ty

.

3.

In addition to the tests above, one set of increasing and decreasing load

and shift tests should be conducted with a power supply of 100 V and one of

130 V. If the scale cannot perform over this range, the scale should be tested

at the minimum and maximum operating voltages provided the power supply does not

exceed the limits of 100 V and 130 V.

If a scale fails the permanence test, the entire test will have to be repeated.

69
9/26/80

DRAFT

Type Approval Criteria

Performance Tests for a Vehicle Scale

and Axle Load* Weighing Element

Performance tests are tests conducted to determine compliance with the

tolerance and, in the case of nonautomatic indicating scales, sensitivity

requirements specified in NBS Handbook 44.

The purpose of the tests is to evaluate the scale design with respect to device

accuracy and repeatability. The performance of a scale should be relatively

installation independent; that is, minor modifications to the general installation

design which can normally be expected in various applications should not change

the scale performance by an amount that is large in relation to the applicable

tolerances. Adjustments to major scale components should have predictable results

A minimum of 30 000 lb (preferably 40 000 lb) of known test weights is needed to

test a scale with a capacity of 120 000 lb or less. A minimum of 40 000 lb of

test weights is needed for a scale with a capacity greater than 120 000 lb through

200 000 lb capacity. More test weights should be used if available. Section

tests may be conducted to the rated capacity of the sections using the available

test weights. All test results should be within acceptance tolerances. Under

these conditions the results from the section tests will automatically agree

with the absolute value of the maintenance tolerances.

Error weight should be used whenever possible to determine the scale error for

beam or digital scales. Ideally, the error should be determined to O.ld values

when possible, especially if only the minimum amount of test weight is available.

It is not necessary to use error weights with dial scales. The errors for dial

scales may be estimated by interpolating between graduations.

Initial Type Approval (Field) Performance Tests

1. Sensitivity tests - Beam scales

Determine the travel of the beam. Beam travel must meet Handbook 44 Scale

Code S.5.1.2. Weighbeam Travel.

The sensitivity test is to be conducted at zero load before each section test

and at the maximum test load for each section. The sensitivity test is to be

conducted from the center of the trig loop to the top and the center of the

trig loop to the bottom of the trig loop. The actual weight required to move

the beam in each direction to the limiting stops should be recorded. The

results up and down are expected to be approximately equal for any given test

load.

* See the NBS Handbook 44 Scale Code definitions for the distinction between

axle load scales and wheel load weighers.

70
Sensitivity tests are to be conducted at the initial load of a strain test

and at the maximum load applied to the scale. The maximum load applied to

a scale to permit the testing of sensitivity near the scale capacity does

not have to be known weights.

The ratio between the sensitivity of the scale at capacity versus the

sensitivity at zero load should not exceed 1.5:1.

2. Section Tests - Example for a four section scale

Section

Test each section of the scale using known test weights. Do not exceed the

section capacity. The load is to be distributed across the section. The load

is to be removed after each section is tested to recheck the zero balance

condition. If two weight carts are used, they should travel along the paths

the wheels of a vehicle would take when moving across the scale. Decreasing

load tests are to be avoided when testing a section. This means a truck cannot

be backed on the scale to lower weights on the inner sections. Decreasing load

tests should be conducted after the sections have been tested to their maximum

load and the weights are being removed from the scale.

If a scale has 18 feet or more between sections, section tests should be con- ducted at the midpoint between sections as well.

If the scale is of a modular design, the section test should first be conducted

by placing the load so it straddles the connection between the modules. Later

at least one section test is to be conducted on the scale where the test load

is first placed on one side of the connection line of the module and then on the side of the connection line. The test load is to be removed between these

tests. The scale error should be determined at a minimum of five equally

spaced test loads. Scale errors may be determined at more points if desired.

The results of the tests must be within acceptance tolerances.

3. Position tests

71
Position test are to be conducted with the test weights concentrated over

each load bearing point of the scale. The load should be removed after each position test if the scale errors are near the tolerance limit or the results

are questionable or if a significant zero balance change has occurred. For

a nH 9 n capacity of n °t more than 120 000 lb, loads of at least 10 000

i?n nnn°?h l u For scales with a capacity of more than

?f

)rough 200 000 1b ’ loads of at least 15 000 and 30 000 or 20 000 and 40 000 lb are to be used for the position tests.

Normally it is expected that the errors for corresponding position tests will sum to the error for the combined loa<d for the section test. For example, if

a load of 15 000 lb on position 1 and 8 had errors of -10 lb and +10 lb

respectively, it is expected that the section error at 30 000 lb should be near

zero.

The results of the tests must be within acceptance tolerances.

4. The section tests as described in step 2 are to be repeated to determine

scale repea tabil ity.

5. Strain load test

Load the scale with vehicles so the addition of test weights will provide a gross load near the scale capacity. Determine the "zero reference point"

for the start of the strain load test. Add the test weights to one of the

end sections of the scale taking care not to overload the section.

Repeat the strain load test on the other end of the scale.

The results of the tests are expected to be within acceptance tolerances which

are applied to the known test load used in the strain load test.

Subsequent Type Approval (Field) Permanence Tests

The subsequent field permanence tests shall consist of complete set of section

tests as described in step 2 but excluding any tests at the midpoints between

sections. Additionally, one strain load test should be conducted on each end

of the scale as specified in step 5.

The time between the initial field permanence test and the subsequent field

test(s) and the tolerances to be applied will be determined by one of the three

alternatives listed in the paper titled, "Permanence Performance Testing for

Scales and Electronic Cash Registers". Until a decision is made by the Task

Force on Type Approval, the set of parameters will be:

(Current method being applied in California)

The field examination to be conducted at an operating test location will consist

of an initial exam followed by two additional field tests for permanence a minimum of thirty days apart. The total duration of the test is normally a minimum of 60 days from the initial test.

72
The initial set of tests will establish the initial errors on a device. All

errors on these tests must be within the acceptance tolerance.

The results of the second and third field examinations for permanence

must be within maintenance tolerance and, in addition, shall not have

changed by more than the absolute value of the acceptance tolerance from

the initial errors for a particular test load in a given test.

If a device fails any of the subsequent permanence tests, the entire perman^

ence test must be repeated. The criteria for repeated permanence tests will

be the method currently being used by California as stated above. It is

anticipated that these cri teria will be used for any repeat field permanence

test regardless of the ultimate choice of alternative permanence tests

selected by the Task Force on National Type Approval.

Caution Regarding Load Concentration

A warning was received that jurisdictions concentrating large loads on scale

platforms by using weight carts or test equipment using hydraulic jacks may

'be in danger of exceeding the maximum pound per square inch load specification

for the deck. This condi ton may arise because the small tire area of the

weight cart in contact with the deck surface could result in a very large

load concentration over an unusually small area. This could cause local

damage to the scale deck.

This situation may occur with weight carts having very narrow or short

wheel bases and small solid rubber tires. This is particularly likely to cause a problem on steel plate decks and could also result in damage to

manhole covers. If the load capacities of weight carts are increased beyond

25 000 lb while maintaining solid tread wheels, then it is possible that some concrete decks could be damaged.

73
9/29/80

DRAFT

Type Approval Criteria

Performance Tests for Platform Scales Except

Vehicle, Railroad, Livestock* and Digital Counter (Bench) Scale

Performance tests are tests conducted to determine compliance with the tolerance

and, in the case of nonautomatic indicating scales, sensitivity requirements

specified in NBS Handbook 44. The purpose of the tests is to evaluate the scale

design with respect to device accuracy and repeatability. The performance of a scale should be relatively installation independent; that is, minor modifications

to the general installation design which can normally be expected in various

applications should not change the scale performance by an amount that is large

in relation to the applicable tolerances. Adjustments to major scale components

should have predictable results.

Scales with a capacity of 20 000 lb or less should be tested to capacity using

known test weights. A minimum of 20 000 lb of test weights should be used on larger scales. Ideally, all scales should be tested to capacity using known

test weights. All test results are expected to be within acceptance tolerances.

Error weights should be used whenever possible to determine the scale error for

beam scales. The guideline titled the "Use of Error Weights on Digital Scales"

may be followed to determine when error weights should be used with digital

scales. It is not necessary to use error weights with dial scales. The errors

for dial scales may be estimated by interpolating between graduations.

Initial Type Approval Performance Tests

1. Sensitivity tests - Beam scales

Determine the travel of the beam. The beam travel must comply with NBS

Handbook 44 Scale Code S.5.2. Weighbeam Travel.

The sensitivity test is to be conducted at zero load and at capacity load. The

sensitivity test is to be conducted from the center of the trig loop to the top

and the center of the trig loop to the bottom. The weight required to move the

beam in each direction to the limiting stops should be recorded. The results

up and down are expected to be approximately equal for any given test load.

The ratio between the sensitivity of the scale at capacity versus the sensitivity

at zero load should not exceed 1.5:1.

2. Increasing load tests -

Three increasing and decreasing load tests should be conducted to determine

device repeatability. A minimum of five different test loads should be applied;

more are preferred. Whenever practical, each notch on a counter (bench) scale

beam should be tested at least once. The results for a given test load under

similar conditions should repeat within the absolute value of the acceptance

tolerance. The term "under similar conditions" refers to the load position on the increasing and decreasing load tests. With respect to repeatability, the

test results from the increasing load test should be reviewed separately from

74
the decreasing load test results. However, the results from both tests are required to be within acceptance tolerances. Similarly, repeatability for

each position in the shift test should be considered separately from the other

shift test positions.

3. Shift tests -

Shift tests are conducted to determine the scale's ability to accurately weigh

off-center loads. The test may also provide information on the structural

design and strength of the weighbridge, the quality control process used to

adjust the corners of the scale and possibly on the sensitivity of the device

accuracy to installation conditions. Bench scales should be tested at one-half

capacity with the load positioned as described in Handbook 112. Larger scales

may be tested by either the corner test method using test weights equal to

one-fourth capacity or the quadrant test (weights centered in each quadrant of

the scale) using weights equal to one-half capacity. The diagrams in Handbook

112 specify the proper positions.

A minimum of three shift tests should be conducted. Ideally two of the shift

tests should be quadrant tests and one should be a corner test. Either test

may reveal a problem that may not appear if only one type of shift test is

conducted.

The results of all increasing load and shift tests conducted during the initial

performance tests must be within acceptance tolerances.

Subsequent Type Approval Permanence Tests

The permanence test for counter and low capacity platform scales which have a capacity of 500 lb or less may be conducted in the laboratory. The procedures

for these tests are described in the paper titled, "Laboratory Permanence Test

for Scales". A field test may be conducted if the results of the laboratory

tests raised questions about the permanence of the device. Under these

conditions, the reasons for conducting a field permanence test will be reported

to the manufacturer.

Scales which cannot be tested in the laboratory are subject to field permanence

tests. The initial type approval performance tests will normally be conducted

at the field site and will start the permanence test phase.

On subsequent permanence test examinations a minimum of one increasing and

decreasing load test and one quadrant shift test should be conducted. If the

test results are marginally within tolerance or out of tolerance, at least

one more series of tests should be conducted to verify the results and determine

device repeatability.

The time between the initial field permanence test and the subsequent field

test(s) and the tolerances to be applied will be determined by one of the three

alternatives listed in the paper titled, "Permanence Performance Testing for

Scales and Electronic Cash Registers". Until a decision is made by the Task

Force on Type Approval, the set of parameters will be:

75
(Current method being applied in California)

The field examination to be conducted at an operating test location will consist

of an initial exam followed by two additional field tests for permanence a minimum of thirty days apart. The total duration of the test is normally a minimum of 60 days from the initial test.

The initial set of tests will establish the initial errors on a device. All errors on these tests must be within the acceptance tolerance.

The results of the second and third field examinations for permanence

must be within maintenance tolerance and, in addition, shall not have

changed by more than the absolute value of the acceptance tolerance from

the initial errors for a particular test load in a given test.

If a device fails any of the subsequent permanence tests, the entire permanence test must be repeated. The criteria for repeated permanence tests will

be the method currently being used by California as stated above. It is

anticipated that thesecri teria will be used for any repeat field permanence

test regardless of the ultimate choice of alternative permanence tests

selected by the Task Force on National Type Approval.

76
9/29/80

DRAFT

Type Approval Criteria

Performance Tests for Digital Counter (Bench)

and Price Computing Scales

Performance tests are tests conducted to determine compliance with the tolerance

and, in the case of nonautomatic indicating scales, sensitivity requirements

specified in NBS Handbook 44. The purpose of the tests is to evaluate the scale

design with respect to device accuracy and repeatability.

Because these scales are normally portable, they are usually supplied with level

bubbles to aid in keeping the scale in a level position. If a portable scale

is not equipped with a level-indicating mechanism, the scale must be tested in

an out-of-level condition in addition to the normal performance tests, to

determine compliance with Scale Code paragraph S.2.3. Leveling-Indicating Means.

The guideline for the "Use of Error Weights on Digital Scales" may be followed

to decide if it is necessary to use error weights to determine scale errors.

Since digital counter (bench) and price computing scales normally have capacities

of 500 lb or less, the permanence test for these scales may be conducted in the

laboratory. The procedures for these tests are described in the paper titled,

"Laboratory Permanence Test for Scales". A field test may be conducted if the

results of the laboratory tests raised questions about the permanence of the

device. Under these conditions, the reasons for conducting a field permanence

test will be reported to the manufacturer.

The laboratory permanence test is strongly recommended for small scales because

it requires less time, is more efficient, is more convenient for the testing

official, and many times is less expensive to the manufacturer. In the event

that a field permanence test must be conducted, procedures are provided below.

Initial Type Approval (Field) Performance Tests

A minimum of two increasing and decreasing load tests and two shift tests are

to be conducted at the start of the field permanence test. The scales are to

be tested to capacity using known test weights. The test results are expected

to be within acceptance tolerance.

Out-of-Level Tests

If a portable scale is not equipped with a level bubble or other level indicating

mechanism, a series of out-of-level tests must be conducted. A scale is considered

portable if its dimensions of length and width are 24 inches by 18 inches or

less, respectively, and the device weighs 35 pounds or less. Regardless of

dimensions, any scale with hand grips or on wheels is considered portable.

First place the scale three degrees or five percent out of level with respect

to the length axis of the scale. The scale should then be rezeroed. Conduct

increasing and decreasing load tests and a shift test. The results must not

have changed by more than the applicable acceptance tolerance from the error obtained when the scale was in a level position.

77
- 2 -

It is suggested that the shift test be conducted first since this test frequently

reveals an accuracy problem.

Next, place the scale three degrees or five percent out of level with respect to

the width axis of the scale. The scale should again be rezeroed. Conduct the

increasing and decreasing load and shift tests. The tolerance application is as stated above.

If the scale fails any of these tests, a level-indicating mechanism is needed.

Subsequent Type Approval (Field) Permanence Tests

One set of increasing and decreasing load tests and one shift test should be

conducted. The scales are to be tested to capacity using known test weights.

If the test results are marginally within tolerance or out of tolerance, at

least one more series of tests should be conducted to verify the results and

determine device repeatability.

The time between the initial field permanence test and the subsequent field

test(s) and the tolerances to be applied will be determined by one of the three

alternatives listed in the paper titled, "Permanence Performance Testing for

Scales and Electronic Cash Registers". Until a decision is made by the Task

Force on Type Approval, the set of parameters will be:

(Current method being applied in California)

The field examination to be conducted at an operating test location will consist

of an initial exam followed by two additional field tests for permanence a minimum of thirty days apart. The total duration of the test is normally a minimum of 60 days from the initial test.

The initial set of tests will establish the initial errors on a device. All errors on these tests must be within the acceptance tolerance.

The results of the second and third field examinations for permanence

must be within maintenance tolerance and, in addition, shall not have

changed by more than the absolute value of the acceptance tolerance from

the initial errors for a particular test load in a given test.

r If a device fails any of the subsequent permanence tests, the entire permanence test must be repeated. The criteria for repeated permanence tests will

be the method currently being used by California as stated above. It is

anticipated that these cri teria will be used for any repeat field permanence

test regardless of the ultimate choice of alternative permanence tests

selected by the Task Force on National Type Approval.

78
8/27/80

Type Approval Criteria

Guidel ine

Use of Error Weights on Digital Scales

The purpose of determining the scale errors in the increasing and

decreasing load tests in a type approval examination is to determine

the accuracy performance curve of the scale. The shift test is conducted

to determine the scale's ability to weigh off-center loads. In both cases,

the scale errors must be checked for compliance to established tolerances.

The most accurate method of determining these errors is by the use of

error weights.

Error weights may be used to test any scale subject to a type approval

examination. When error weights are used, the one-half scale division

for digital indications (Handbook 44 Scale Code T.1.3.) will not be

applied. The scale must perform within acceptance tolerances.

The determination of errors in a digital scale by the use of error

weights is a slow process. When the tolerance applied to a scale at a capacity load consists of several scale divisions, the accuracy performance curve can be determined quite reliably by reading the scale

error directly from the displayed weight values. Whenever the scale

error is determined by direct reading, the tolerance that would normally

be applied should be increased by one-half of a scale division as stated

in NBS Handbook 44 Scale Code T.1.3. . This is necessary because the

actual weight value may be plus or minus one-half of a scale division

from the displayed weight value. This additional tolerance is provided

so the scale is not penalized by the direct reading of the scale errors.

If the scale error as determined by direct reading exceeds the direct

reading tolerance, the scale is out of tolerance.

To aid weights and measures officials to determine when to use error

weights to determine scale errors and when to direct read scale errors,

the following guidelines are suggested for type approval examinations:

(a) If a scale has 5000 scale divisions or more and the scale is tested

to capacity using known test weights, then the direct reading of

scale errors is satisfactory. In this case if the scale tolerance

is 0.05%, then the direct reading tolerance at capacity is three

divisions.

(b) Scale errors are to be determined by using error weights when the

total amount of test weights represents less than 5000 scale divisions.

(c) Computing scales may be tested by the direct reading of errors because

the scales are generally well within tolerance and many tests can

be run easily in a short period of time to collect many data points

for the accuracy performance curve. If the test results are marginal

with respect to the tolerance the error weights should be used.

79
( 2 )

(d) Scale errors can be determined in type approval tests by direct

reading if the display resolution can be increased by a factor of

ten times the actual resolution being requested for type approval.

This is particularly applicable to scales which would normally have

less than 5000 scale divisions in the weight range covered by the

application of known test weights. The increased resolution would

give readings equivalent to that obtained by using error weights

equal to 0.1 scale division. The width of zero, zero tracking, and zone of uncertainly tests must be conducted with the scale resolution

set for the maximum number of divisions being requested for type

approval

.

80
9/26/80

Test of a Digital Scale Using Error Weights

This test method is applicable to any digital scale. The explanation

will be given for a 120 000 x 20 lb vehicle scale. The letter "d" will

mean scale division. A scale division is defined as the difference

between two consecutive numbers on a digital scale. For the vehicle

scale above, the scale division will be 20 lb. Each displayed weight

value will have a range of weight over which the scale will display a specific weight value. For example, the vehicle scale above will theoretically display the weight value 50 000 lb over a weight range of

49 990 lb to 50 010 lb because a digital device is required to round off

weight values.

This means a scale division has a certain "width" or range over which it

indicates that particular weight value. When a weight value is used

with the word "division", it will identify the particular scale division

being discussed. In the example above this was the 50 000 lb division.

To test a scale using error weights, it is necessary to know "where you

are" within a scale division; i.e., to have a reference point. The

"zero reference point" will be the point within the zero division at

which the scale is located when it is under zero load. This is explained

in more detail later. The most useful values for the zero reference

point are the center of zero or the leading or trailing edge of the zone

of uncertainty.

The smallest weight value that will be added or removed from the scale

will be O.ld. The use of weight values this small will stretch the

limits of readability of the scale and will have an uncertainty of at

least O.ld depending upon the scale, the installation, and environmental

conditions. This uncertainty is recognized along with the repeatability

of the scale and is considered when reviewing data taken to the O.ld

even though no further comments will be made about this uncertainty in

the remainder of this explanation.

The term "breakpoint" will be used to refer to the edge of the zone of

uncertainty (zu) on either end of a division. For example, if the scale

does not have zero tracking, the addition of weight in O.ld steps will

eventually result in the scale alternately displaying 0 or Id or a fixed

Id (20 lb in the example below). The point where the scale first starts

to enter the zone of uncertainty will be called the breakpoint.

A word of caution is needed about microprocessor-based scales that make

use of built-in hysteresis or "anti jitter" programs. This is becoming a common feature in digital electronic scales and is used to reduce the zone of uncertainty and provide a very stable indication. Basically,

built-in hysteresis means that once a scale has selected a particular

weight value to be displayed, a change in weight of approximately O.ld

to 0.2d is required to change the weight display although the scale may

81
actually be in what is normally the zone of uncertainty. This is not zero tracking because the weight may be applied in small steps and this

will produce the same result as if the weight were applied in one step.

This makes the zone of uncertainty or breakpoint appear to move about

depending upon the direction (above or below) in which the zone of

uncertainty is approached.

This discussion can be visualized by considering each digital scale

division as being comprised of ten smaller divisions each having a value

of O.ld. The center of a division is between the two middle O.ld smaller

divisions.

-2d

-40

-Id

-20

II il

Id

20

111

2d

40

3d

60

±L ni

Breakpoint

at low

end of zero

Maximum

width of zone of

uncertainty

(0.3d)

Breakpoint

at high end

of zero

Range over

which scale

gives a stable

indication

If a scale is equipped with zero tracking, we can normally assume the zero reference point is at the center of the zero division.

-20 20

t

I I 1 M II 1

zero reference

poi nt

Low end

of zero division

High end

of zero division

82
If a scale is not equipped with zero tracking, the zero reference point

(the point from which the scale starts within the zero division) may be

anywhere within the zero division.

-20 0 20

Zero reference point may be

anywhere within the zero division

To test a digital scale by using error weights, it will be convenient to

select the center of zero as the zero reference point. Initially, place

error weights on the scale and adjust the zero mechanism to obtain a zero display. If the scale has zero tracking, it can be assumed that

the zero reference point is at the center of zero. If the scale does

not have zero tracking, it is necessary to adjust the zero mechanism or change the error weights to set the zero reference point at the center

of zero.

For scales without zero tracking first determine the width of the stable

zero indication. This is done by removing weight from the scale in O.ld

steps. Eventually you will reach the breakpoint on the low edge of zero. Add O.ld to return you to a stable zero indication. This will put you

just within the stable zero division on the low edge of zero and is your

starting point to determine the width of zero.

Edge of

stable zero division

(START)

83
Now add weight in multiples of O.ld (2 lb) to get close to the breakpoint on the high end of the zero division. .Continue to add weight in

O.ld (2 lb) steps until you just enter the zone of uncertainty (breakpoint) on the high end of zero.

(START) Breakpoint

The amount of weight added from the start position is considered to be

the width of the zero division. Although the final added weight step

placed you at the breakpoint, this is not considered to put the scale at

a disadvantage to meet the width of zero requirement because the start

position was in the stable zero division and conceivably could have been

almost O.ld inside the low end of the zero division when the test started.

At this time it is convenient to test the width of the zone of uncertainty

because you have worked your way to the breakpoint on the high end of

the zero division. Add weight in O.ld (2 lb) steps until a stable 20 lb

(Id) indication is obtained. This should not require more than 0.3d (6

lb) since the zone of uncertainty is required to be less than or equal

to 0.3d.

Return to the breakpoint on the high end of the zero division. Remove

half the weight that represented the width of zero. This will put the zero reference point at the center of the zero divison. Equal weight

will have to be added or removed to reach the breakpoints on the high

and low ends of the zero division.

20 lb 0 20 lb

-101b I 101b

n8 -16-14-12 I -8 -6-4 -2 +2 4 6 8 I 12 14 16 13

i i i i 1 i ii I I r i i i 1 i i i „l

zu T

Zero

reference

point

zu

84
jj Suppose that 5 OOO. lb were applied to the scale and that the zone of

uncertainty is 0.2d or 4 lb. Suppose the scale indicates a stable 5 000

lb on the display. To determine the scale error, add weight in 2 lb

steps (O.ld) until the breakpoint on the high end of the 5 000 lb division

is reached. If only 2 lb is added to reach the breakpoint, the scale

has an error of +6 lb since the scale is on the high end of the 5 000 lb

division when the scale started at the center of the zero division,

i This condition is illustrated as follows:

10

| I 2 4 6 8 1 12 1416 j-1-.l.J I I I I I I 1 I i l

|

V

zero reference

point

At zero, 8 lb were required to reach the breakpoint while at 5 000 lb

only 21b were required to reach the breakpoint on the high end of the

division. The error can be computed as

8 lb - 2 lb = 6 lb

which is

(weight needed at zero) - (weight needed at test load) = error.

Suppose 14 lb had to be added to reach the breakpoint on the high end of

the 5 000 lb division. The error would be

8 lb - 14 lb = -6 lb

This can be drawn as

20 4980 5000

-6 4-2 I IJJJ JJ J .1111

5020

Zero

reference

point

t

S7

-14 lb

>| -

breakpoint

85
This means that the final scale position is 6 lb below the center of the

division. Since the zero reference point was the center of the zero division, the error is -6 lb.

Suppose that the test load were increased to 20 000 lb and that the

scale indicated a stable 20 020 lb. We would know that the scale indication

represents a weight between 20 012 and 20 028 (16 lb range) since the zone of uncertainty is 4 lb wide. Suppose that only 4 lb were needed to

reach the breakpoint on the high end of the 20 020 lb division. This

could be represented as

20 20 000 lb 20 020 20 040

10

2 4 6 8 | 12 14 16 18 J i i i IT i i i

22

1 » i

1 1 Mil

k

j

4 lb

f > reference

Zero f

poi nt

This scale error could be counted from the center of the 20 000 lb

division to reveal an error of 24 lb. This could be computed as follows:

weight needed

at zero to

breakpoint

8 lb

weight needed indication

at test load + error = scale error

to breakpoint

4 lb 20 lb = 24 lb

Suppose that the scale indicated 19980 lb and that 12 lb were needed to

reach the breakpoint. The scale error would be computed as

8 lb - (12) + (-20 lb) = -24 lb

This can be verified on the diagram as:

0 20 19 960 19 980 20 000 lb

10 2 4 6 8 | 12 14 16 18 J i 1 M 1 I 1 I I I 1 t V-10

lint -24-22 -18-16-14-12 .-8-6 4-2

I < I I 1 M I I

I I w

Zero

reference

point

jp

7

12 lb This point

represents zero error«

86
Notice in these examples that weight was always added to reach the

breakpoint on the high end of the display division. For simplicity

this is the only method described. This method of calculation is

valid even if the indication error is more than one division.

>

87
' • ? > > •• ' - • ' 1 '
NBS-114A (REV. 2-8C) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

1. PUBLICATION OR

REPORT NO.

2. Performing Organ. Report No. 3. Publication Date

SHEET (See instructions) NBSIR 80-2179 December im 4. TITLE AND SUBTITLE

raft Type Approval Criteria and Test Procedures

5. AUTHOR(S)

Henry V. Oppermann

6. PERFORMING ORGANIZATION (If joint or other than N8S, see in struction s)

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

7. Contract/Grant No.

8 . Type of Report & Period Covered

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State. ZIP)

Same as Item 6

10.

SUPPLEMENTARY NOTES

_J Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11.

ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significan-t

bi bliography or literature survey, mention it here)

This document is a preliminary draft of a possible handbook on type approval criteria

and procedures for weighing and measuring devices. The distribution of the draft is to

solicit comments on whether the information is useful to manufacturers and weights and

measures officials. The responses will determine if further development of written

type approval criteria in the measurement areas covered in the draft and in other

measurement areas should be pursued.

The development of checklists and test procedures is an effort to make both the manufacturer and the enforcement official aware of criteria currently being used in type

approval examinations. It is also an attempt to standardize the criteria and test

methods. The distribution of this draft document will provide a basis for discussion

of possible directions for a national type approval program in the future. The checklists and test methods are intended to be sufficiently flexible to be easily changed to

keep pace with technology and to permit innovation in the design of weighing and

measuring equipment.

12.

KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolops)

digital indication; error weights; performance tests; permanence tests; scale division

tare; test weights; tolerances; type approval.

I

13. AVAILABILITY

Uni imited

UQO For Official Distribution. Do Not Release to NTIS

Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.

Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

94

15. Price

USCOMM-DC 6043-P80
_