Adam Equipment CBC 15, Service Manual

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@Adam Equipment Company 2005
11
Place this weight on the scale and press the [Tare] key after the stable symbol is on.
The display will now show the second weight needed. This will be full capacity.
Place the weight on the platform and press the [Tare] key again after the stable symbol is on.
When the scale begins its start up procedure the weights can be removed and calibration is
complete.
Suggested Factory Calibration weights:
CBC SERIES
CBC 3 CBC 6 CBC 15 CBC 30 CBC 45
Weight 1 1000 g 2 kg 5 kg 10 kg 15 lb
Weight 2 3000 g 6 kg 15 kg 30 kg 45 kg
CBCa SERIES
CBC 6a CBC 12a CBC 35a CBC 65a CBC 100a
lb kg lb kg lb kg lb kg lb kg
Weight 1 2 lb 1000g 4 lb 2 kg 10 lb 5 kg 20 lb 10 kg 40 lb. 15 kg
Weight 2 6 lb 3000g 12lb 6 kg 30 lb 15 kg 60 lb 30 kg 100 lb 30 kg
8.0 LOAD CELL DAMAGE
The most common reason a scale fails is that the load cell has been damaged. The damage
can be from 2 primary causes. The first is physical damage due to an overload or an impact
from the side and the second is damage due to the environment, such as moisture, extreme
heat or a cut cable if the cables are exposed.
PRINCIPLE OF OPERATION
The stain gauge load cell is a method of measuring the amount of stress put onto a metal
structure due to a weight being supported by the structure. The stress is measured using 4
strain gauge sensors mounted in a particular way on the metal structure.
These 4 strain gauges are connected in such a way that they form a wheatstone bridge. See
figure below. In the simplest load cells there are only the 4 resistances of the strain gauges to
consider. Normally without a load on the load cell all the resistances are the same. However
when the load cell has a weight on it 2 of the strain gauges will be in compression (A and D)
and the resistance will decrease and 2 will be in tension (B and C) and their resistance will
increase.