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Crane scale cable weight compensation system
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Application Requirement
Overhead crane scales with load cells located in the trolley require compensation for the weight of the cable/wire from which the “hook” is suspended.
Customer Concern
The weight of the wire or cable from which the “hook” is suspended must be subtracted from the live weight signal to maintain accurate readings and proper overload control. Weight values must be subtracted dynamically as the cable/wire is payed out and then reeled back in.
Vishay Solution
Vishay Nobel measures the exact length of the cable/wire using an incremental encoder mounted on the crane pulley. The resulting encoder output (pulse train) feeds into a load cell instrument, which translates the pulse length into a weight equivalent. After subtracting the weight equivalent value, resulting weight signals remain precise and linear throughout the lifting operation.
Compensated weight readings can be transmitted to a large display or radio control device using either a 4-mA to 20-mA or Fieldbus output.
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