Legal Metrology Act, 2014 (Act No. 9 of 2014)RegulationsLegal Metrology Regulations, 2017Part XI : Measuring instruments and containers used for prescribed purposes68. Weighing instruments: Position of balance and means of balancing at zero load |
| (1) |
| (a) | Unless otherwise prescribed in a technical regulation relating to a specific type of instrument, the position of balance of a weighing instrument at zero load must be indicated— |
| (i) | in the case of a vibrating weighing instrument, by the beam or steelyard returning to the horizontal position of equilibrium when disturbed therefrom; |
| (ii) | in the case of a self-indicating or semi-self-indicating weighing instrument with analogue indication and in the case of a weighing instrument provided with a difference chart, by the index coming to rest at the zero graduation, or vice versa; and |
| (iii) | in the case of a self-indicating weighing instrument with digital indication, by the number "0" appearing on the main indicator and the balance indicator, where provided, being at zero balance position. |
| (b) | In the case of any weighing instrument provided with a spirit level or other level indicator to indicate its reference position, the position of balance prescribed in this subregulation must be indicated when the weighing instrument is in its reference position. |
| (c) | Paragraph (a) of this subregulation must not apply in the case of a weighing instrument approved in terms of section 22 of the Act if such measuring instrument is so constructed as not to be in balance or not to indicate zero when unloaded. |
| (2) |
| (a) | Except as otherwise provided in any regulation of this Part or in terms of the approval of a weighing instrument under section 22 of the Act— |
| (i) | every weighing instrument must be provided with a means for balancing the measuring instrument at zero load, in accordance with any appropriate provision of subregulation (1); |
| (ii) | a self-indicating weighing instrument with digital indication must be provided with a means for indicating the position of balance at zero load: Provided that, where the balance indication is itself digital or not continuous, the weighing instrument must be correct within one quarter of the value of the smallest graduation of the main indicator when the position of balance is indicated. |
| (b) |
| (i) | Except as otherwise provided in any regulation of this Part where the balance of a weighing instrument at zero load is manually adjustable by means of a continuously operating rotatable device, one full turn(360⁰ rotation) of such device must not affect the position of balance by more than 0,1% of the capacity of the weighing instrument, or in the case of a self-indicating weighing instrument by more than 0,1% of the capacity of such weighing instrument or by more than the value of the smallest graduation of such weighing instrument, whichever is the lesser. |
| (ii) | The means for balancing a zero load of any weighing instrument, other than a weighing instrument having only digital indication, must operate continuously when being adjusted. |
| (iii) | The means for balancing at zero load of a weighing instrument having only digital indication may operate in discrete steps, the value of each step being not more than one quarter of the value of the smallest graduation of the weighing instrument. |
| (c) | On a new or repaired weighing instrument the means for balancing must be equally adjustable either way when the weighing instrument is submitted for verification by a mechanic or it has been repaired or maintained by such a person. |
| (d) |
| (i) | Except as otherwise provided in any regulation of this Part a weighing instrument, which has digital indication may be provided with a device which, when set in operation by means of a push-button, automatically resets the indication to zero. |
| (ii) | Where a device referred to in subparagraph (i) does not also adjust the balance in accordance with any appropriate provision of subregulation (1), an additional device must be provided for balancing as required. |
| (e) |
| (i) | Except as otherwise provided in any regulation of this Part, a weighing instrument may be provided with a device which automatically maintains the weighing instrument in balance at zero load or which automatically compensates, in the indication of the result of a measurement, for an out of balance condition at zero load. |
| (ii) | A device referred to in subparagraph (i) may be an apparatus for setting the indication to zero when the load is within a pre-determined range about zero or in an appropriate case and where approved in a certificate issued in terms of section 22 of the Act an apparatus known as an "automatic calibrator", for periodically simulating a pre-determined load, comparing this with the indication and, within a pre-determined range, adjusting the indication to correspond with the simulated load, thus in effect compensating for an out of balance condition at zero load. |
| (iii) | A device referred to in subparagraph (i) must be so arranged that the zero load balance is maintained or imbalance is compensated for so as to be within one quarter of the value of the smallest graduation of the main indicator and so that zero is indicated when there is no load on the weighing instrument. |
| (iv) | Any means provided for switching a device referred to in subparagraph (i) out of operation must not be available to an operator. |
| (v) | The operation of any device referred to in subparagraph (i) must be delayed for such a period and the pre-determined range of the device must be so limited, taking the delay period into consideration, that the device does not operate during the placing of any load on the load receptor of the weighing instrument by any means normally employed for placing such load. |