TS–020 Additional non-approved indicator for summing readings from multiple approved indicators on weighing instruments

Scope

The policy provides the requirements for an additional non-approved indicator when used for summing weighing results obtained from multiple primary approved indicators.

Reference documents

Policy

Each approved weighing instrument must be verified or inspected individually. An Accredited Person (AP) must confirm the summing function on the non approved summing indicator during a verification or inspection test. This test requires a load of 250 e (where ‘e’ equals the verification scale interval of that scale) to be placed on each load receptor and the resultant mathematical summed indication must be correct. This should be recorded on the test sheet.

For Example:

Scale 1:

Maximum capacity = 15000 kg

Verification scale interval = 5 kg

Test Load = 250 e = 1250 kg

Indication = 1250 kg

Scale 2:

Maximum capacity = 30000 kg

Verification scale interval = 10 kg

Test Load = 250 e = 2500 kg

Indication = 2500 kg

The summing indicator must display the correct mathematical sum, which in this example is Scale 1 Indication + Scale 2 Indication = 1250 + 2500 = 3750 kg.

The installation must comply with the following:

  • The indication displayed on the summing indicator must represent the mathematical sum of the measured values displayed on the other two primary approved indicators.
  • The scale interval on the summing indicator shall be appropriate for the scale intervals of the primary approved indicators being summed. The following examples are provided:
  • Example 1
    • Scale 1 – ‘e’ = 5 kg
    • Scale 2 – ‘e’ = 10 kg

Therefore on the summing indicator, ‘e’ must be 5 kg, so it can indicate the mathematical sum of the primary approved indications.

  • Example 2
    • Scale 1 – ‘e’ = 20 kg
    • Scale 2 – ‘e’ = 50 kg
    • Scale 3 – ‘e’ = 20 kg

Therefore on the summing indicator, ‘e’ must be 10 kg indications, so it can indicate the mathematical sum of the primary approved indications.

  • The summing indicator must blank or show non-numeric characters if any one of the primary approved indicators is blanked (over max capacity)
  • If the summing indicator is capable of showing one or all primary approved indicator values along with the summed value, then the individual primary approved indicator values must be identified on the summing indicator
  • When product is placed on both load receptors for weighing, all load receptors must be installed level and on the same plane.

Tip Icon Blue2 NOTE

Primary indicators which have been issued with a Certifcate of Approval and cover a summing function are not covered by this policy.

Difference between trade approved and non approved weighing instrument

Trade Measurement — Technical Policy

Policy number:TS - 020
Effective date: July 2016
Version number: 2
Policy name: Additional non-approved indicator for summing readings from multiple approved indicators on weighing instruments
Reviewed by: Davis White, Legal Metrology Advisor and Senior Trading Standards Officer
Approved by: Phil Sorrell, Team Leader Compliance and Inspection