Seca 780 - Description of the calibration mode for scales with modular electronics; General; Calibration counter; Recalibrating the scales

Vogel & Halke
Created on: 30.06.1998
Holger Panier/ SE
File: 00603_el.doc
Printed on: 07.07.1999
seca
Description of the calibration mode for scales with modular
electronics
General:
Seca scales with modular electronics are fitted with a software-controlled calibration device
that is operated using the existing controls. This device can be used to recalibrate the
scales or to set the scales to different GAL values. During development of the calibration
device, special attention was paid to the following requirements:
• It must be possible to recalibrate the scales without any additional external
equipment/tools.
• It must be possible to calibrate the calibration device.
• It must be possible to recalibrate the scales without calibrated test weights.
• The calibration device shall be protected against inadvertent use.
Calibration counter
The scales fitted with the new, modular electronics are equipped with a calibration counter
allowing a software recalibration to be carried out according to the requirements for
calibrated scales. To carry out such a recalibration, the calibration counter setting can be
called up on the display of the scales and compared to the data given on the calibration
label mark (applies only for calibrated products). If the values are identical, the scales are
calibrated; whereas differing values match the situation of a broken calibration seal. Each
completed recalibration procedure is registered by the calibration counter, i.e. the number is
automatically incremented by 1.
Recalibrating the scales
Before the scales can be recalibrated, they must be switched to the calibration mode:
To do so, switch on the scales using the appropriate control. While doing so, simultaneously
press another control key (for example, the kg/lbs key). This causes the contents of the
calibration counter (i.e. the number of calibration procedures carried out so far) to be
displayed for five seconds (flashing).
During the 5 seconds the contents is displayed, press the kg/lbs key again and keep it
depressed (for more than 1.5 seconds) to switch the scales to the calibration mode.
If the kg/lbs key is not pressed within these 5 seconds, the scales are automatically
switched back to normal weighing operation.
When switched to the calibration mode, the scales first are in a decrementing state. This
state is indicated by a flashing "dec" that alternates with the currently measured weight.
Now place a test weight onto the scales. This test weight should have a weight of at least
25% of the maximum permissible load for the weight (we recommend a weight of approx.
66-75%). The weight shown on the display must match the test weight; otherwise, the
scales are maladjusted and the recalibration procedure must carried out in full length. To do
so, change the weight shown on the display using the kg/lbs key until it matches the test
weight.
If the value shown on the display differs from the test weight (if not, recalibration is not
required), estimate whether the required nominal weight is easier to reach by decrementing
or by incrementing. To toggle from the decrementing mode to the incrementing mode or
vice versa, press the kg/lbs key for more than 1.5 seconds (display indicates dec or inc).
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