Description
The below table is a UKAS (United Kingdom Accreditation Service) guideline for selecting the most appropriate calibration weight for your weighing scale.
|
Weighing Scale Resolution |
||||||
|
Weighing Scale Capacity |
100g | 10g | 1g | 100mg | 10mg | 1mg |
|---|---|---|---|---|---|---|
| Up To 500g | M3 | M3 | M3 | M2 | F2 | E2 |
| Up To 1Kg | M3 | M3 | M3 | M1 | F1 | E1 |
| Up To 5Kg | M3 | M3 | M2 | F2 | E2 | |
| Up To 10Kg | M3 | M3 | M1 | F1 | E1 | |
| Up To 50Kg | M3 | M2 | F2 | E2 | ||
| Up To 100Kg | M3 | M1 | F1 | |||
| Up To 500Kg | F2 | E2 | ||||
Technical Specification
Each classification specifies maximum error discrepancies from a nominal value. The classification given to a calibration weight also depends upon its material, density, corrosion resistance, hardness, wear resistance, brittleness, magnetic properties, construction, and surface finish.
| M2 | |
|---|---|
| Notation | Precision weights for testing, calibrating and adjusting trade balances. |
| Error Discrepancy | The maximum error discrepancy from nominal value at 1 kg is 160mg. |
| Material/Shape
|
1g to 2Kg: Cylindrical, Finely Turned Brass
5Kg to 20Kg: Rectangular, Cast Iron Lacquered |
Other OIML Classifications
| E1 | |
|---|---|
| Notation | Weight standards of the highest accuracy class, mostly only used as reference standards for metrological services. |
| Error Discrepancy | The maximum error discrepancy from nominal value at 1Kg is 0.5mg. |
| Material/Shape | 1mg to 500mg: Wire Shape, Stainless Steel
1g to 20Kg: Knob Shape, Polished Stainless Steel. |
| E2 | |
| Notation | The most accurate test or adjusting weights for high resolution, high precision weighing scales. |
| Error Discrepancy | The maximum error discrepancy from nominal value at 1 kg is 1.6 mg. |
| Material/Shape | 1mg to 500mg: Flat polygonal sheet, Polished Stainless Steel
1g to 20Kg: Cylindrical, Polished Stainless Steel |
| F1 | |
| Notation | High precision weights suitable for testing, calibrating and adjusting most high precision weighing scales. |
| Error Discrepancy | The maximum error discrepancy from nominal value at 1 kg is 5 mg. |
| Material/Shape
|
1mg to 500mg: Flat polygonal sheet, Polished Stainless Steel
1g to 10Kg: ECO-Shape, Polished Stainless Steel 20Kg: Cylindrical, Polished Stainless Steel |
| F2 | |
| Notation | High precision weights suitable for very accurate precision balances. Ideal weight classification for weighing applications involving high value commercial transactions, e.g. precious stones. |
| Error Discrepancy | The maximum error discrepancy from nominal value at 1 kg is 16mg. |
| Material/Shape
|
1mg to 500mg: Flat polygonal sheet, Polished Stainless Steel
1g to 20Kg: Cylindrical, Finely Turned Stainless Steel |
| M1 | |
| Notation | Precision weights for trade weighing scales. |
| Error Discrepancy | The maximum error discrepancy from nominal value at 1 kg is 50mg. |
| Material/Shape
|
1mg to 500mg: Flat polygonal sheet, Polished Stainless Steel
1g to 2Kg: Cylindrical, Finely Turned Brass 5Kg to 20Kg: Rectangular, Cast Iron Lacquered |
| M3 | |
| Notation | Trade weights for everyday use with weighing scales. |
| Error Discrepancy | The maximum error discrepancy from nominal value at 1 kg is 500mg. |
| Material/Shape
|
Cast Iron Lacquered |
OIML Classes of Accuracy
| Nominal Weight | E1 | E2 | F1 | F2 | M1 | M2 | M3 |
|---|---|---|---|---|---|---|---|
| 1mg | ±0.003 | ±0.006 | ±0.02 | ±0.06 | ±0.2 | - | - |
| 2mg | ±0.003 | ±0.006 | ±0.02 | ±0.06 | ±0.2 | - | - |
| 5mg | ±0.003 | ±0.006 | ±0.02 | ±0.06 | ±0.2 | - | - |
| 10mg | ±0.003 | ±0.008 | ±0.025 | ±0.08 | ±0.25 | - | - |
| 20mg | ±0.003 | ±0.01 | ±0.03 | ±0.1 | ±0.3 | - | - |
| 50mg | ±0.004 | ±0.012 | ±0.04 | ±0.12 | ±0.4 | - | - |
| 100mg | ±0.005 | ±0.016 | ±0.05 | ±0.16 | ±0.5 | - | - |
| 200mg | ±0.006 | ±0.02 | ±0.06 | ±0.2 | ±0.6 | - | - |
| 500mg | ±0.008 | ±0.025 | ±0.08 | ±0.25 | ±0.8 | - | - |
| 1g | ±0.01 | ±0.03 | ±0.1 | ±0.3 | ±1 | ±3 | - |
| 2g | ±0.012 | ±0.04 | ±0.12 | ±0.4 | ±1.2 | ±4 | - |
| 5g | ±0.016 | ±0.05 | ±0.16 | ±0.5 | ±1.6 | ±5 | - |
| 10g | ±0.02 | ±0.06 | ±0.2 | ±0.6 | ±2 | ±6 | - |
| 20g | ±0.025 | ±0.08 | ±0.25 | ±0.8 | ±2.5 | ±8 | - |
| 50g | ±0.03 | ±0.1 | ±0.3 | ±1 | ±3 | ±10 | - |
| 100g | ±0.05 | ±0.16 | ±0.5 | ±1.6 | ±5 | ±16 | - |
| 200g | ±0.1 | ±0.3 | ±1 | ±3 | ±10 | ±30 | - |
| 500g | ±0.25 | ±0.08 | ±2.5 | ±8 | ±25 | ±80 | - |
| 1Kg | ±0.5 | ±0.16 | ±5 | ±16 | ±50 | ±160 | - |
| 2Kg | ±1 | ±3 | ±10 | ±30 | ±100 | ±300 | - |
| 5Kg | ±2.5 | ±8 | ±25 | ±80 | ±250 | ±800 | ±2500 |
| 10Kg | ±5 | ±16 | ±50 | ±160 | ±500 | ±1600 | ±5000 |
| 20Kg | ±10 | ±30 | ±100 | ±300 | ±1000 | ±3000 | ±1000 |