TS–009 Discrimination test on digital weighing instruments

Scope

To prescribe the maximum acceptable load required to perform a discrimination test on a digital weighing instrument.

Reference documents

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 loadInstrument 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 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