An instrument which is made in accordance with an approved pattern and which is marked Y(a) is a Class Y(a) instrument. The specifications for a Class Y(a) instrument are as follows—

An instrument which is made in accordance with an approved pattern and which is marked Y(b) is a Class Y(b) instrument. The specifications for a Class Y(b) instrument are as follows—

The installation of an automatic catchweighing instrument shall be so designed that an automatic weighing operation will be the same whether for the purposes of testing or for use for a transaction.

Every automatic catchweighing instrument shall be positioned so as to facilitate cleaning and testing.

Instruments with dynamic setting shall have a facility for any access to dynamic setting to be automatically and non-erasably recorded.

Maximum capacity (Max) and minimum capacity (Min) shall be specified by the manufacturer.

The minimum capacity shall not be less than:

Instruments shall comply with the appropriate metrological and technical requirements at temperatures from –10°C to +40°C. However, for special applications the limits of the temperature range may differ from those given above but such a range shall not be less than 30°C and shall be specified in the descriptive markings.

Where an automatic catchweighing instrument is marked with a temperature range it shall not be used for trade in temperatures outside that range.

Instruments which are not intended for installation in a fixed position and which do not have a level indicator shall comply with the appropriate metrological and technical requirements when tilted by 5%.

Where an automatic catchweighing instrument is fitted with a level indicating device it shall enable the instrument to be set to a tilt of 1% or less.

Where an automatic catchweighing instrument is marked (in accordance with Schedule 4) with a mark which signifies the purpose or manner of use, it shall not be used for a purpose or in a manner which does not accord with that marking.

Instruments of Class Y(b) shall only be used for weighing ballast or waste or other goods in accordance with the particulars of the approved pattern.

For the purposes of the second paragraph of the preceding section of this Schedule (Specified purpose or manner of use), “waste” shall be construed in accordance with Article 2(2) of the Waste and Contaminated Land (Northern Ireland) Order 199712, provided that “waste” shall include any waste disposed of for reprocessing or recycling purposes but shall not include any radioactive waste as defined in section 2 of the Radioactive Substances Act 199313.

An automatic zero-setting device shall operate:

• only when the stability criteria are fulfilled

• sufficiently often to ensure that the zero is maintained within 0.5 e.

A non-automatic zero-setting device shall not be operable during automatic operation.

A semi-automatic zero-setting device shall function only when the stability criteria are fulfilled.

A zero-tracking device shall operate only when:

• the indication is at zero, or at a negative net value equivalent to gross zero, and

• the stability criteria are fulfilled, and

• the corrections are not more than 0.5 e/second.

A semi-automatic or automatic tare device shall operate only when the stability criteria are fulfilled.

A non-automatic or semi-automatic tare device shall not be operable during automatic operation.

An instrument shall be designed to suit the method of operation and the loads for which it is intended. It shall be of adequately robust construction in order that it maintains its metrological characteristics.

Printing a weighing result below minimum capacity shall not be possible.

There shall be no indication above Max + 9 e.

An automatic catchweighing instrument shall not be used above the maximum rate of operation.

Instruments shall bear the following markings.

• name or identification mark of the manufacturer

• name or identification mark of the importer (if applicable)

• serial number and type designation of the instrument

• maximum rate of operation (if applicable) in the form: … loads per minute

• maximum speed of load transport system (if applicable) in the form: … m/s

• electrical supply voltage in the form: … V

• electrical supply frequency in the form: … Hz

• working fluid pressure (if applicable) in the form: … kPa

• adjustment range referred to set point (if applicable) in the form: ± … g or % (of set point value)

Depending upon the particular use of the instrument, supplementary markings may be required on pattern approval by the metrological authority issuing the pattern approval certificate, (e.g. temperature range.)

Additional markings may be required on initial verification to specify types of packs and related weighing conditions.

Descriptive markings shall be indelible and of a size, shape and clarity that permit legibility under normal conditions of use.

They shall be grouped together in a clearly visible place on the instrument, either on a descriptive plate fixed near the indicating device or on the indicating device itself. It shall be possible to seal the plate bearing the markings, unless it cannot be removed without being destroyed.

The descriptive markings may be shown on a programmable display which is controlled by software. In this case, means shall be provided for any access to reprogramming of the markings to be automatically and non-erasably recorded, e.g. by traceable access software. When a programmable display is used, the plate of the instrument shall bear at least the following markings:

• type and designation of the instrument

• name or identification mark of the manufacturer

• pattern approval number

• electrical supply voltage

• electrical supply frequency

• pneumatic pressure.

Instruments shall have a place for the application of verification marks. This place shall:

• be such that the part on which it is located cannot be removed from the instrument without damaging the marks

• allow easy application of the mark without changing the metrological qualities of the instrument

• be visible without the instrument or its protective covers having to be moved when it is in service.

Instruments required to bear verification marks shall have a verification mark support, at the place provided for above, which shall ensure the conservation of the marks.

When the mark is made with a stamp the support may consist of a strip of lead or any other material with similar qualities, inserted into a plate fixed to the instrument, or in a cavity bored in the instrument.

Automatic catchweighing instruments shall bear the additional descriptive marking “R51” which shall be presented in accordance with the provisions of clause 3.9.2 of Part 1 of OIML R51.

(Principle from Clause 2.3 of OIML R51)

The maximum permissible error for any load equal to or greater than the minimum capacity (Min) and equal to or less than the maximum capacity (Max) in automatic operation shall be as specified in Table 1. (Note that the mpe-value includes the digital rounding error of the indicating device.)

(Principle from Clause 2.5.2 of OIML R51)

The maximum permissible error for any load equal to or greater than the minimum capacity (Min) and equal to or less than the maximum capacity (Max) for static weighing in non-automatic operation shall be as specified in Table 2.