LDU 179.1 Technical Manual rev. 1.10 - February 2019 Page 45 of 45
9.
Use in “Approved” Applications
The term
“approved” applies whenever the weighing application is intended to be used for “legal-for-trade”
weighing
– that is, money will change hands according to the weight result. Such applications are bound by the
legal metrology regulations of the relevant governments around the World, but most countries will comply with
either the relevant EN’s (Euro Norms) or the relevant OIML (Organisation Internationale de Metrologie Legale)
recommendations.
The LDU 179.1 has been approved as a component for use in weighing systems according to OIML
recommendation R76, the highest performance level approved being Class III, 10 000 intervals(e) in single
range, multi-range and multi-interval applications. The approval Authority was the Danish Electronics, Light &
Acoustics (DELTA), and the approval certificate number is DK0199-R76-xxxxx
This approval will allow the use in approved weighing systems throughout Europe, and in many other countries
of the World. To achieve approval on a particular application, it will be necessary to satisfy the relevant
Governmental Trading Standards Authority that the requirements of the various rules and regulations have
been satisfied. This task is greatly simplified if the key components of the weighing system, namely the load
cells and the weighing indicator or digitizer, are already approved as “components”.
Usually, a discussion with the Weighing Equipment Approvals Officers at the relevant National Weights &
Measures Office will then reveal the extent of any pattern testing that may be necessary to ensure compliance.
Restrictions upon usage when in “Approved” applications
A number of performance restrictions must come into force. These restrictions are the number of display
divisions, which become limited to 10000 divisions, and the sensitivity per display division, which becomes
0.2
μV per division. Once installed in the application, an “approved” application will require “stamping” by an
Officer of the relevant Governmental Trading Standards Department. This certifies the equipment or system as
being in accordance to the relevant regulations and within calibration limits.
The Traceable Access Code (TAC)
The user software must then provide a guard against improper access of the calibration commands (see the
“Calibration Commands” section). The LDU 179.1 digitizer features the “Traceable Access Code” or TAC
method of controlling the access to the calibration commands group. This means that a code is maintained
within the device, and is incremented whenever any change to any of the calibration commands is saved.
When performing the “stamping” test, the Trading Standards Officer will make a note of the TAC, and advise
the user that any change to this code which occurs prior to the regular re-inspection by the Trading Standards
Office, will result in legal prosecution of the user.
The user software is required as a condition of approval, to make the TAC available to the weight display
indicator or console, on demand.
www.haubac.com
