Rockwell Automation 9329 Drive Application Software - Manual (Page 25)

FM – Diameter Calculation
Drive Application Software – page 25 of 30
If the Calculated Diameter return parameter (DiamCalc - Ret1) is not accurate:
1. Hand tach the roll surface and verify that the correct value of Line Speed
(DiamCalc - In4). Finally, monitor motor speed and verify the correct value of
Motor Speed (DiamCalc – In5).
Note: The diameter calculator is only as accurate as the Line Speed and Motor
Speed input parameters (DiamCalc – In4, In5). For example, if a line speed
reference signal is used for the Line Speed input parameter, lead section speed
errors, lead section calibration errors, dancer loop velocity, and/or material stretch will
contribute to differences between the actual surface speed of the roll and the Line
Speed input parameter value.
If the Calculated Diameter return parameter (DiamCalc - Ret1) is accurate but is
fluctuating:
1. Increase the Diameter Calculator Update Interval (DiamCalc – In3) and use a
whole number of revolutions. Using a whole number of revolutions for the
Diameter Calculator Update Interval will help reduce fluctuations due to roll
eccentricity.