Calibration
Locking and Unlocking Calibration
VT300 Technical Manual, Rev. A4
36
Doc # TM-VT300-EN
4.5 Locking and Unlocking Calibration
An internal jumper (JP1, located on the main printed circuit board next to the analog
circuit) must be removed to allow access to configuration and calibration parameters.
One way to seal the indicator is to prevent access to this jumper. This is done by
placing a brittle plastic sticker over one of the screws that keeps the cabinet closed.
The indicator also has an
Audit Trail Counter
, which is incremented every time weight
parameters or calibration data are changed, regardless of whether the change was
saved in EEPROM or not. This counter allows the authorities to check if any calibration
attempt has been made since the last inspection.
A label with an inscribed count (all digits are permanently printed and suffixed
by a hyphen) is placed on the rear side of the instrument. The label is
designated
CAL-Nr
, and may not be removed without destroying it.
Seals bear the verification mark of a notified body, or an alternative mark of
the manufacturer, according to Annex II, section 2.3 of Directive 90/384/EEC.
4.5.1
Sealing Indicator Enclosure with Stickers
After calibration, you can seal the indicator with two stickers:
A non-removable label, to prevent unauthorized opening of the indicator
enclosure (Figure 8)
A lead wire seal or hard plastic sticker, to prevent unauthorized tampering with
the load cell connector (Figure 9)
Figure 8 – Non-removable sticker
Figure 9 – Lead wire seal / hard plastic sticker
