Page 54 Accumass BW500 PL-565
Recalibration
Linearization
Conveyor applications where the ideal belt scale location has been compromised, or
where there is a high degree of variation in belt tension, typically cause the belt scale
to report load non-linearly. The BW500 provides a linearizing function (P390 - P392)
in order to correct for the deficiency in the weighing system and to provide an
accurate report of the actual process.
To verify that the cause of the non-linearity is not mechanical:
• run the conveyor belt empty and stop it.
• Lift the belt off of the scale and suspend various test weights to the scale to verify
mechanical linearity. If the load reported by the BW500 at these tests is non-linear, a
mechanical problem is indicated. Refer to the belt scale manual in order to resolve
the non-linearity by improved installation or repair.
If it is determined that the non-linearity is due to the weighing application, and not the
actual belt scale, apply linearization by performing the following:
• zero calibration
• span calibration at 90 to 100% of design rate
• material tests at 90 to 100% of design rate
• manual span adjust if required
• material tests at 1 to 5 intermediary flow rates where compensation is required.
Note:
Compensation points must be at least 10% of the design load apart.
• calculate the percentage compensation for each flow rate tested.
% compensation = actual weight - totalized weight x 100
totalized weight
where:
actual weight = material test
totalized weight = BW500 total
Notes:
• After the compensation has been programmed into the BW500, a material test
should be run to verify the effect of linearization.
• If additional compensation is required, it must be based on new material tests
performed with the linearization turned off (P390 = 0).
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