Siemens Milltronics SF 500, Инструкция по эксплуатации, Страница: 52 / 134

Page 46 Milltronics SF 500 – INSTRUCTION MANUAL 7ML19985CN01
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Recalibr
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Linearization
In applications where the ideal flowmeter location has been compromised, or where
there is a high degree of variation in flow rates, the flowmeter may report rate non-
linearly. The SF 500 provides a linearizing function (P390 - P392) to correct for this
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:
• Stop the feeding system.
• Remove the flowmeter cover and suspend increasingly heavier test weights to the
sensory mechanism to verify mechanical linearity. For each test weight, note the
flow value. If the rate reported by the SF 500 is non-linear, a mechanical problem is
indicated. Refer to the flowmeter manual to resolve the non-linearity.
If it is determined that the non-linearity is due to the weighing application,
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
• repeat material tests at 1 to 5 intermediary flow rates where compensation is
required.
• 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 = SF 500 total
Note:
Compensation points must be at least 10% of the design load apart.
Note:
• After programming the compensation into the SF 500, run a material test 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).