Short Title
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1.
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These specifications may be cited as the Weights and
Measures Specifications SGM-1.
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Authority
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2.
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These specifications are established pursuant to section 13 of
the Weights and
Measures Regulations, C.R.C., c.1605. (SI/98-27)
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Interpretation
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3.
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In this specification, "scale" means any weighing
machine to which these specifications apply. (SI/98-27)
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Application
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4.
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Except as may otherwise be allowed by a Notice of Approval these
specifications apply to any electronic digital indicating
computing scale capable of use in trade with electronic
components that has minimum increments of registration of 0.01
pound or less and 10 grams or less; these specifications are to
be read in conjunction with the Weights and
Measures Act and Weights and
Measures Regulations.
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Motion Detection
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5.
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Except as may otherwise be allowed by a Notice of Approval, a
scale shall incorporate a non-operator controlled motion
detector to prevent the recording of a weight signal until the
load receiving element is stable within + 1 minimum increment of
registration.
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5.1
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The load receiving element shall be stable as required by 5., at
least 0.4 second before a weight signal is recorded.
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5.2
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The motion detector and automatic zero control circuits shall be
interlocked so that use of the latter is inhibited during
operation of the former.
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Platter Lock
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6.
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A scale incorporating a platter locking system shall be designed
and constructed such that the system does not interfere with the
zero balance display, and it shall be inoperative until the load
receiving element is stable as in 5.
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Electronic Indicators
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7.
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The contrast between any digital display and the background
shall have a ratio equal to or greater than 4 to 1.
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7.1
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A scale shall incorporate a test system for verifying that all
display segments are neither continuously on nor off; such test
system shall permit verification of display segments without the
need for any tools or by a self-verifying automatic system that
indicates the occurrences of any failure.
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Free Floating Weight Signal
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8.
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In order to allow for adjustment of commodities to a desired
weight before the settled weight is used for computation, the
weight signal used for computing the total price must be free
floating until entry for computation.
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Weight Units
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9.
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Associated with any digital weight registration there shall be
suitably located an appropriate name, symbol or abbreviation for
the unit of measurement registered.
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Capacity Indication
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10.
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No digital indicating element or recording element shall
register any value when the load exceeds the rated capacity of
the scale by more than 10 minimum increments of registration.
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Customer Indication
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11.
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Exempt as may otherwise be allowed by a Notice of Approval, any
scale equipped with a digital registration for the operator
shall have duplicate displays for the customer.
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Construction and Design to Facilitate Inspection
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12.
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Except as may otherwise be allowed by a Notice of Approval,
means shall be provided to seal only the coarse zero and span
adjustment controls so that all other components and adjustments
are readily accessible without breaking the seal; such means
shall be readily observable upon inspection without the
necessity of disassembling any part requiring the use of
mechanical means separate from the scale.
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Zero
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13.
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When a scale displays a weight value less than zero, the total
price indicator shall not display any value and recording
elements shall be interlocked to inhibit the recording of
negative weight values.
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13.1
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The maximum zero range of the type which may be adjusted from
the scale exterior shall not exceed 4 per cent of rated
scale capacity; unless operable only by a detachable tool, when
activated, such adjustment mechanism shall only return the scale
to a zero balance condition.
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13.2
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Automatic means to maintain a digital zero balance condition
shall be non-operator controlled and the maximum load that may
be placed on the load receiving element, with the scale
indicating zero and "rezero" without indicating a
weight value, shall be a mass equal to 0.6 of a minimum
increment of registration.
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13.3
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The maximum zero range of an automatic means of maintaining zero
shall not exceed 4 per cent of rated scale capacity.
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Tare
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14.
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The tare mechanism shall operate only in the direction of
under-registration with respect to the zero load balance
condition of the scale, and a negative weight indication shall
continue to be displayed when the load receiving element is
empty.
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14.1
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When the tare mechanism is functioning there shall be visual
confirmation on or adjacent to the weight display that the tare
mode is operating.
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14.2
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A scale may be equipped with full scale tare; however, the gross
weight shall not exceed the rated capacity of the scale within
the limits given in paragraph 10.
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14.3
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A tare mechanism shall be self-cancelling, that is, when any net
weight is added to the tare, the total is computed and the gross
amount if removed from the scale, the weight indication shall
return to a zero balance condition in accordance with regulation
183, unless the scale is in the pre-packing mode.
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14.4
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An automatic tare control shall be identified with the word
"TARE", the letters "TR", or words or
letters that convey the same meaning.
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14.5
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Except as may otherwise be allowed by a Notice of Approval, a
tare entry shall only be erased from the scale memory with the
removal of gross load from the weighing element; entry of
another price per unit of weight, use of a "clear"
mechanism or any other keying sequence shall not affect the tare
entry.
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14.6
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A scale incorporating a tare mechanism shall incorporate a power
failure interlock providing a means whereby temporary loss of
power to the scale will prevent a further scale operation
without requiring a very obvious reset operation; when there is
a loss of power to a scale all means of indicating that the
scale is in the tare mode shall extinguish and remain
extinguished when power returns.
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14.7
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Except as may otherwise be allowed by a Notice of Approval, the
minimum increment of tare shall be the same as the minimum
increment of registration.
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14.8
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The use of any mechanism to convert units of measurement (for
example, lb/kg switch) shall be inhibited when tare is entered
in a scale, unless this mechanism converts all values of weight
registration when activated.
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Price Per Unit of Weight Indicator
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15.
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Any scale other than one for pre-packing use shall clear all
digital indication of total price and price per unit of weight,
and shall extinguish the tare indication when either the
commodity is removed from the weighing element or before another
commodity is weighed and its price computed.
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Pre-Packing Mode
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16.
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When a scale is in the pre-packing mode there shall be a visual
confirmation of this on both the operator and customer sides of
the scale, whether by the legend "FOR PRE-PACKING USE"
or words that convey the same meaning.
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Level Indicating Means
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17.
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A scale shall be equipped with a level indicating means which
shall be readily observable without the necessity of
disassembling any scale part requiring the use of mechanical
means separate from the scale.
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Registration of Monetary Value
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18.
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Any registration of monetary value shall be in mathematical
agreement with the quantity indication and unit price, and shall
be "rounded off" to the nearest minimum unit as
follows:
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when the figure next beyond the last figure or place to be
retained is less than 5 the figure in the last place
retained shall be kept unchanged;
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when the figure next beyond the last figure or place to be
retained is 5 followed by any figure other than zero or is
greater than 5, the figure in the last place retained
shall be increased by one.
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Withstanding Variations
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19.
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Except as may otherwise be allowed by a Notice of Approval, the
scale shall meet or exceed the performance criteria of the Weights
and Measures Regulations, when tested after being
calibrated and zeroed, under any possible combinations of the
following operating conditions:
ambient temperature - 10°C to 40°C
relative humidity 10% to 95%
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19.1
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The weighing element shall withstand vertical forces to 150% of
the rated capacity without affecting calibrations, and to 300%
of rated capacity without permanent degradation.
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19.2
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A scale shall be capable of operating within + 10% of its
voltage rating and + 2% frequency variation of its frequency
rating.
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Load Indication
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20.
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For the same load kept on a scale, the difference between the
indication obtained at the moment of placing the load and the
indication obtained eight hours later shall not exceed the
permissible acceptance limit of error for loads applied set out
in Division 6 of the Weights and
Measures Regulations.
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20.1
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The variation on returning to zero after the removal of a load
which has remained on the scale for half an hour may not exceed
one-half the finest digital increment of registration.
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20.2
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The no load indication shall not vary by more than one minimum
increment of registration for a difference in ambient
temperature of 5° C.
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Miscellaneous
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21.
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A scale shall meet or exceed the performance criteria prescribed
by the Weights and
Measures Regulations and by these specifications when
tested at a constant ambient temperature, that is, a temperature
that does not vary more than 5°C.
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21.1
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A scale shall meet or exceed the performance criteria of the Weights
and Measures Regulations when scanned at a distance of
2 metres with
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a 460 MHz (commercial) 4 watt, hand-held communicator,
and
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a 27 MHz (citizen's band) 4 watt, hand-held
communicator.
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Measurement Canada
