Linearization - Siemens Milltronics BW500 Operating Lnstructions

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 and BW500/L provides a linearizing function (P390 -
P392) 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.
If the load reported by the BW500 and BW500/L is non-linear, a mechanical problem
is indicated. Refer to the belt scale manual 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.
Compensation points must be at least 10% of the design load apart.
Note:
• calculate the percentage compensation for each flow rate tested.
% compensation = actual weight - totalized weight x 100
where:
actual weight = material test
totalized weight = BW500 and BW500/L total
Note:
• After the compensation has been programmed into the BW500 and BW500/L, 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).
7ML19985DK05Milltronics BW500 and BW500/L - OPERATING INSTRUCTIONS
totalized weight
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