HBK Z7A, Mounting Instructions, Page: 8 / 52

Z7A
NOTES ON MOUNTING
6
3 NOTES ON MOUNTING
The following must be considered during the assembly of load cells:
S
The load cell must be handled with care.
S
Do not overload the load cell, not even for a short time, for example, by impact forces
during mounting or unevenly distributed supporting forces.
S
The load cell seating must be horizontal, flat over the whole surface and, like the load
cell base, absolutely clean.
S
The fundament must be unyielding in relation to the expected loads.
S
Dust, dirt and other particles are not to accumulate such that they affect the load cell's
mobility and thus falsify the measured value.
S
Every load cell should be shunted by a stranded copper cable (approx. 16 mm
2
, e.g.
EEK... from HBM) during or immediately after installation to prevent any welding cur­
rents from flowing through the load cell.
S
In load cells with an additional outer braided wire over the cable (item no. K-Z7A_ with
options 6R or 12R), this cable is only used for protection against increased mechani­
cal stress (e.g. damage caused by gnawing rodents). To avoid accidental energiza­
tion, the outer braided wire must be connected to potential equalization at least once.
This outer braid is not used to shield the load cell. The inner braid of the load cell ca­
ble is used for shielding.
Notice
Never load the transducers against the indicated load direction (see arrow on the load
introduction side). This results in measuring errors and can damage the fixing bolts. With
the correct load direction and electrical connection, the output signal of the load cells is
positive.
The load cells are fixed at the mounting bores like a cantilever beam, the load is applied
at the other end. For the recommended screws and tightening torques refer to the table
below:
Max. capacity Thread Min. property
class
Tightening torque
1)
Frict. coeff.
μ
= 0.125
0.5...2 t 2 x M12 10.9 115 N m
5 t 2 x M20 10.9 560 N m
10 t 2 x M24 10.9 970 N m
1)
Recommended value for the stated property class. For screw dimensioning please refer to the
appropriate information given by the screw manufacturers.