TS–009 Discrimination test on digital weighing instruments
This policy prescribes the maximum acceptable load required to perform a discrimination test on a digital weighing instrument.
Reference documents
- Weights and Measures Regulations 1999(external link)
- Regulation 57 – Discrimination
Policy
Regulation 57 of the Regulations requires a discrimination test to be performed at:
- Minimum capacity
- Half maximum capacity
- Maximum capacity
The regulation states that for a digital weighing instrument, a load of not more than 1.4 of a scale interval when applied to or removed from the load receptor must create a change in the reading.
It is therefore acceptable to use a load of ≤1.4 x scale interval to perform this test.
| Discrimination test load | Instrument type |
|---|---|
| 1.4 x d | Instruments fitted with auxiliary indicating devices where ‘e’ is not equal to ‘d’ and d ≥ 5 mg. |
| 1.4 x e | Instruments fitted with auxiliary indicating devices where ‘e’ is not equal to ‘d’ and d< 5 mg. |
| 1.4 x e | Instruments, where ‘e’ = ‘d’. (e.g. Class III and IIII) |
In Class III and IIII instruments, where delta loads ( = to 1/10th of ‘e’ ) are used to determine an error in a weighing instrument at minimum, half maximum or maximum capacities, and those applied delta loads (up to 1.4 x e) cause the instrument to discriminate to the next division, the instrument will be considered to have passed the discrimination test at that load.
Trade Measurement — Technical Policy
| Policy number: | TS - 009 |
|---|---|
| Effective date: | August 2016 |
| Version date: | October 2016 |
| Version number: | 3 |
| Policy name: | Discrimination test on digital weighing instruments |
| Reviewed by: | Davis White, Legal Metrology Advisor and Senior Trading Standards Officer |
| Approved by: | Phil Sorrell, Team Leader Compliance and Inspection |