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Edition 06/2009
Insulation resistance
•
Disconnect the load cell.
•
Connect all lines.
•
Measure insulation resistance between lines and load cell housing
•
Measure insulation resistance between lines and cable shield
•
Measure insulation resistance between cable shield and load cell housing (This
measurement is not possible in load cells in which the shield is connected to
the load cell housing).
The insulation resistance must match the value in the technical data
Input and output resistance
•
Disconnect the load cell.
•
Measure the input resistance between EXC+ and EXC-.
•
Measure the output resistance between SIG+ and SIG-.
The resistances must match the values in the data sheet or the technical data.
Bridge resistance
•
Disconnect load cell.
•
Measure resistance between SIG- and EXC-
•
Measure resistance between SIG+ and EXC+
The difference between the two values may not be greater than 1Ω.
The measurement cannot be made in the series K load cell.
DANGER
Measurements may not be made on the load cells in the Ex area.
CAUTION
Do not use ohmmeters which feed more voltage into the load cell than permitted
in the technical data to measure the resistance.
A frequent cause of error which leads to failure of the load cells is their
overloading. If overloading is diagnosed as the cause of the error, further
measures are necessary. Damage is often caused by one of the following:
1. Dynamic overloading, e.g. by accidental falling of a relatively small weight onto
the load carrier from a great height.
Possible remedies:
•
•
SIWAREX R Load Cells Operating Manual
A5E00159640
Fit shock-absorbing components, e.g. elastomer bearings
Overdimension the load cells
Service
20
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