TS–010 Span adjustment of a weighing instrument following the completion of all required tests
This policy details the procedure to follow when performing a span adjustment on instruments with a maximum capacity > 1000 kg. Weighing Instruments of ≤ 1000 kg must be tested at all Maximum Permissible Error (MPE) change points following a span adjustment.
Following the successful completion of all required tests on a weighing instrument with a maximum capacity > 1000 kg, and the instrument is determined to be operating outside the allowable MPE with linear errors, this policy provides the Accredited Person provision to span the instrument and to retest at the 500 e MPE change point only.
- Weights and Measures Act 1987(external link)
- Weights and Measures Regulations 1999(external link)
- Regulation 55 – Zero setting devices
- Regulation 59 – Test loads
Where a weighing instrument with a maximum capacity > 1000 kg has been tested and found to have errors outside of MPE and those errors are linear and a span adjustment is performed, the following procedure applies:
- Immediately following a span adjustment, all loads are removed from the load receptor and the instrument is returned to zero
- The accuracy of the zero is confirmed as per Regulation 55 of the Regulations
- The accuracy of the span adjustment is confirmed by applying the test load specified in Table 1 below; the indicated value for the test load applied must be documented on the test sheet
- The linear error is confirmed as being within the MPE tolerances for on verification as provided in Table 1 below
- The instrument is then deemed to have passed all required tests.
|Class of Instrument||Test Load in ‘e’||On Verification MPE ‘e’|
|Class III||500||+/- 0.5|
|Class IIII||50||+/- 0.5|
Trade Measurement — Technical Policy
|Policy number:||TS - 010|
|Effective date:||July 2016|
|Policy name:||Span adjustment of a weighing instrument following the completion of all required tests|
|Reviewed by:||Davis White, Legal Metrology Advisor and Senior Trading Standards Officer|
|Approved by:||Phil Sorrell, Team Leader Compliance and Inspection|