Field inspection manual—dimensional measuring devices

Table of contents


1.0 Introduction

1.1 Introduction

There should exist a similarity in attitude, procedure and performance by all Measurement Canada personnel and recognized technicians of accredited or registered organizations performing the same general inspections. Uniform application and consistent interpretation of legislation, policies and procedures is key to the effective administration and enforcement of the Weights and Measure Act, Regulations and Ministerial Specifications.

The purpose of this Field Inspection Manual is to provide inspectors and other interested parties with a guide to the inspection of Dimensional Measuring Devices (linear, area, solid volume and time). Each test procedure includes the actual Standard Test Procedures (STP) which provides detailed criteria for testing the device or system. If required, reference is made to other test procedures, specifications and legislation.

The use of these test procedures to evaluate the compliance of an dimensional measuring device or system should be considered the norm rather than the exception. In some circumstances, additional tests may be warranted. In cases such as these, the Regional Specialists should be consulted, and care must be taken to ensure that these tests adhere to the intent of the Weights and Measures Act, Regulations and other Specifications.

Enforcement action shall be initiated when an infraction sufficient enough to warrant non compliance with the legislation is identified. The enforcement strategy shall be in accordance with the Weights and Measures Enforcement Policy for Weighing and Measuring Devices.

Measurement Canada encourages the reference and use of test procedures and test equipment as identified in this manual, but acknowledges that there are alternative test procedures or test equipment that can be used to inspect a weighing or measuring device. Subject to the review and approval of the proposed test procedure or test equipment by Measurement Canada, the alternative methodology will be accepted and documented in the respective Standards Test Procedure (STP) on a case-by-case basis.

Revision

Original document

1.2 Symbols, acronymns and definitions

AZSM
Automatic Zero-Setting Mechanism
d
Actual Scale Interval
DUT
Device Under Test
e
Verification Scale Interval
emin
Minimum Verification Scale Interval
EMI
Electromagnetic Interference
IPO
Inspection Procedure Outlines
IZSM
Initial Zero-Setting Mechanism
Laboratory
Measurement Canada Laboratory
MC
Measurement Canada
Max
Maximum Capacity
MZSM
Manual Zero-Setting Mechanism
NOA
Notice of Approval
nmax
Maximum Number of Scale Intervals
OIML
Organisation internationale de métrologie légale
PLU
Code Price Look Up Code
POS
Point-of-Sale Weighing System
RFI
Radio Frequency Interference
SAZSM
Semi Automatic Zero-Setting Mechanism
STP
Standard Test Procedures
ZU
Zone of Uncertainty
Automatic Weighing Device
A weighing device that weighs without the intervention of an operator and follows a predetermined program of automatic processes characteristic of the device.
Catch Weighing Device ACWD
An automatic device that weighs pre-assembled discrete loads or single loads of loose material. Includes "Automatic Overhead Rail Scales" and "Automatic Belt Scales". Does not include those devices commonly known as "Conveyor Belt Scales".
Discontinuous Totalizing Weighing System DTWS
An automatic device that weighs bulk product by dividing it into discrete loads, determining the mass of each discrete load in sequence, summing the weighing results and delivering the discrete loads to bulk. Often referred to as "Bulk Weigher".
Continuous Totalizing Weighing System CTWS
An automatic device for continuously weighing a bulk product on a conveyor belt, without systematic subdivision of the mass and without interrupting the movement of the conveyor belt. Often referred to as "Conveyor Belt Scale".
Rail Weighing Device [IMRR]
An automatic device having a load receptor, inclusive of rails for conveying railway cars and that determines the total mass of a train or, of an individual car, by weighing while in-motion.
In-Motion Vehicle Weighing Device IMVW
An automatic device having a load receptor(s) that determine the total mass of a vehicle by weighing the vehicle while in-motion.
Gravimetric Filling Device
An automatic device which fills containers with predetermined and virtually constant mass of product from bulk by automatic weighing, and which comprises essentially an automatic feeding device or devices associated with one or more weighing units and the appropriate control and discharge devices. This will be considered an automatic packaging machine.
Non-Automatic Weighing Device
A weighing device that weighs discrete loads and that requires an operator's intervention during the weighing process, such as to deposit the load to be measured on the weighing and load-receiving element and to remove it therefrom or to obtain weighing results. If there is doubt whether a device should be included as an Automatic or Non-Automatic Weighing Device, the Non-Automatic designation shall prevail.

Revision

Original document.

2.0 Procedures

2.1 Linear measuring systems

2.1.1 Type 90-10: dynamic linear measures

Application

Carpet and Flooring Material measuring machines.

Equipment
Purpose

The purpose of this test is to determine whether the carpet and flooring measuring machine under test (from here on in this document referred to as the DUT or Device Under Test) is capable of measuring within applicable tolerances and under the conditions for which it may be used. These test procedures are minium test requirements; if conditions warrant it additional tests may be necessary.

Procedures
Preparing the test samples

L.1.0 Test samples

As a minium the test samples selected are:

Note: For approval purposes, select samples in both metric and Canadian units. For initial and subsequent inspections, select samples according to the units of use.

L.1.1 Test strip

If a suitable sample is not available or it is not practical to measure the sample on site, a test strip of carpet and linoleum can be made up prior to the inspection. The test strips should be at least 5 metres (16 feet) long or 10 revolutions of the measuring wheel, whichever is greatest, and be at least 1 metre wide. Care must be taken in drawing the sample through the DUT as the feeding mechanism may cause the test strip to move laterally.

L.1.2 Marked points

Using your certified length standard, mark the underneath of the test sample at the following points (if it is not possible to mark the underneath of the sample, mark it with a piece of tape or by using other suitable means):

Ensure that all points marked on the test sample correspond to a certified length as indicated on the calibration certificate for the length standard being used; otherwise, mark other points as close to the recommended points as possible. In addition, ensure that the length standard is used as prescribed on the calibration certificate, for example, the zero point is that of the designated zero point conditions listed on the certificate. Lastly, ensure that the ambient temperature when marking the test sample is above 12 °C.

Figure 1

Marked point as mentioned in section L.1.2
Performance

L.2.0 Conditions and set up

The performance tests shall be performed in a manner simulating the actual manner of use. Hence, the test sample shall be measured by placing it in the same position as it would be measured in trade (e.g., the measuring wheel touching the back of the product or the top, product hanging from a rack, etc.). Place the test sample through the DUT and ensure that the marked zero is aligned with the cutting edge of the DUT and re-zero the device. Throughout the test, use the cutting edge on the DUT as your measuring reference point.

L.3.0 Slow speed test

Measure the test samples using the DUT by drawing each sample at the slowest speed at which the device is capable of functioning and also manually if this is a possible operating mode. Place the test sample through the DUT, align the zero mark with the cutting blade and re-zero the device. Verify the registrations of the DUT at each metre of the test samples and record the associated registrations. Repeat for a total of three times per test sample.

Data for all three tests must be within the limits of error in order for the DUT to comply (Reference to R214, 215, 218, 219 of the Regulations).

L.4.0 High speed test

Measure the test samples using the DUT by drawing each sample the test length at the fastest speed at which the device is capable of functioning. Place the test sample through the, align the zero mark with the cutting blade and re-zero the device. Verify the registrations of the DUT at each metre, beyond 5 metres, of the test samples and record the associated registrations. Repeat for a total of three times per test sample. If the test sample is less than 6 metres long then only one measurement (5 metres) need be verified for each high speed test.

Data for all three tests must be within the limits of error in order for the to comply (Reference to R214, 215, 218, 219 of the Regulations).

L.5.0 Roll back test and zeroing

If the DUT does not prevent the occurrence of rollbacks, verify at least once that rolling back the material does not create a significant measurement error.

Check this by deliberately rolling back 50 cm of material between the 3 m point and the 4 m point. Place a test sample through the DUT, align the zero mark with the cutting blade and re-zero the device, then perform the following sequence:

The DUT is deemed to comply with the requirements if:

L.6.0 Backlash test

Verify at least once that the backlash (in the gears of the measuring mechanism) does not create significant measuring errors.

Check this by deliberately stopping and re-starting to measure the test sample. Verify this at maximum operating speed between the 3 m and the 4 m point. Place a test sample through the DUT, align the zero mark with the cutting blade and re-zero the device, then perform the following sequence:

All recorded registrations must be within the limits of error in order for the DUT to comply (Reference to R213).

L.7.0 Slippage test

Using the test sample with the least friction (most slippery), verify at least once that slippage does not create significant measuring errors.

Check this by deliberately stopping and then advancing abruptly the test sample. Verify this at maximum operating speed between the 3 m and the 4 m point. Place the test sample through the DUT, align the zero mark with the cutting blade and re-zero the device, then perform the following sequence:

All recorded registrations must be within the limits of error in order for the DUT to comply (Reference to R211).

L.8.0 Limits of indication test

Using the longest test sample, verify that the device does not measure beyond the stated capacity.

The device shall not provide any indication beyond the maximum capacity for which it is approved.

Revision

Original document.

2.1.2 Type 90-10: mechanical linear measures

Application

Fabric Measuring devices and wire/rope/cord measuring devices.

Equipment

Fabric tape measure standard and product representative of that measured on the machine.

Performance
Fabric measuring devices:

Insert the testing tape between the rollers and advance tape zero to the stop.

Note: Care should be taken to avoid notching the tape standard.

Set all dial indicators to zero and close rollers on tape.

Advance tape slowly, pulling with one hand and guiding with the other.

Check the tape at each 10 centimeters (4 inches) up to the metre (yard) and then again at each metre (yard), for the entire length of the tape. Note any errors.

Check the backlash by stopping the tape at a selected graduation, advance the tape several centimetres (inches) and then return it to the selected graduation. Any variance is the backlash error.

Repeat the procedure to determine repeatability of the device.

Wire/rope/cord measuring devices:

Open the rollers and place the wire, rope or cord between them.

Set all dials to zero and pull a length of wire, rope or cord through the machine, laying it on a straight flat surface.

Check the length with a 20 metre (50 foot) tape standard.

Use various diameters and compositions of wire, rope or cord.

Pull the wire, rope or cord through the machine at various speeds to check for error due to slippage.

Check the backlash by stopping the device, during a test run, at a selected graduation, advancing the device several centimetres (inches) and then returning it to the selected graduation. Any variance is the backlash error.

Repeat procedure to determine the repeatability of the device.

Revision

Original document.

2.1.3 Type 90-10: static linear measures

Application

Rigid Measures and tape measures used in trade.

Equipment

Tape measure standard.

Performance
Rigid measures:

Position the standard on the rigid trade measure such that the two series of graduations are brought together.

Shift the position of the standard into precise alignment with the zero of the rigid trade measure.

Compare the total interval of the measure with its nominal equivalent on the standard.

Compare at least six intervals, from zero to each of six intermediate graduations.

Tape measures:

Position the standard on the measure so that one series of graduations will partially overlap the other, the tapes being supported on a horizontal flat surface.

Shift the position of the upper tape, as required to bring the zero graduations of the standard and the measure into precise alignment.

Apply the prescribed tensions, as accurately as possible to both tapes.

Compare the total interval of the measure with its equivalent on the standard.

Compare at least six intervals, from zero to each of six intermediate graduations.

Note: If the static measure under inspection is non-verified, the approval number and the words "Legal For Trade" shall be defaced.

Revision

Original document.

2.2 Area measuring systems

2.2.1 Type 90-10, 91-10, 99-10: area measuring devices

Reference

Weights and Measures Regulations.

Purpose

Measurement of Area.

General

This test procedure is under development. Contact your Gravimetric Specialist for current requirements.

This document is issued as a place holder only.

2.3 Multi dimensional measuring systems

2.3.1 Type 90-20: multi dimensional measuring devices

Reference

Weights and Measures Regulations.

Purpose

Measurement of Multiple Dimensions.

General

This test procedure is under development. Contact your Gravimetric Specialist for current requirements.

This document is issued as a place holder only.

2.4 Time measuring systems

2.4.1 Type 99-10: time measuring devices

Reference

Weights and Measures Regulations.

Purpose

Measurement of Time.

General

This test procedure is under development. Contact your Gravimetric Specialist for current requirements.

This document is issued as a place holder only.

3.0 Appendice

Date modified: