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LDU 68 Series Manual
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7
USE IN “APPROVED” APPLICATIONS (LDU 68.1 ONLY)
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 ENs (Euro Norms) or the relevant
OIML (Organization Internationale de Metrologie Legale) recommendation
The LDU 68.1 has been approved as a component for use in weighing systems according to OIML
recommendations R76, the highest performance level approved being Class III & Class IIII, 10000
divisions. The approval authority was the Danish Electronics, Light & Acoustic (DELTA) and the
approval certificate number is DK0199-R76-10.04, dated 25.02.10. This approval will allow the use
in approved weighing throughout Europe and many other countries in 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 digitiser, 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 1.0uV 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 68.1 digitiser 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.
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TECHNIQUES LIMITED
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LDU 68 Series Manual
8
SOFTWARE (FIRMWARE) DOWNLOAD
To download new firmware into the LDU XX.X, you will require a Windows PC with an USB port
and an USB to RS422 converter. The solder pad SW5 (See page 6) on the under side of the PCB
has to be closed (linked across) before switching on the power. After downloading the new
firmware the link has to reopened.
All files required to download new firmware (LduDownload.exe, prog78.a20 & LduXX.a20) must be
stored in the same directory. The actual firmware to be downloaded is in the file LduXX.a20. These
files will be provided by your local LDU supplier on request.
Remove the power to the LDU XX.X.
Link the solder pads SW4 on the back of the LDU XX.X with a solder bridge.
Power up the LDU XX.X
Start the “LduDownload” program.
Press the “Load” button and choose the “LduXX.a20” file
Press the “Program” button
When the message “Reset LDU before proceeding” appears, switch the LDU off and wait 5
seconds. Re-apply the power and press “OK”
The download will now proceed - When the download is complete the “Programming OK” message
will be displayed.
Switch off the LDU and remove the solder bridge from the SW5 pads on the back of the LDU PCB
Now use the DOP program or a terminal program (such as Hyperterminal) to run the Factory Reset
command (FD)
Please note that the FD command is TAC protected. You must issue the CE command with the
relevant TAC code prior to the FD command otherwise the FD command will fail.
8.1 Firmware update for LDU XX.X series
Issue 1h
