Emerson FM-3 manual Velocity Group, Enable Separate Distance Units Check Box, Scaled Distance Name

FM-3 Programming Module Reference Manual

If the user decides to put a 5:1 reducer on the system, the user simply needs to change the Characteristic Length.

Now the belt travels 4.71" in 5 motor revolutions.

Characteristic Distance = 4.712

Scaling = ---------------------------------------------------------------------------

Characteristic Length = 5

Keep in mind that the characteristic length is always a whole number and the valid range is from 1 to 2000.

Note

User Units may affect end motor speed and could cause trajectory faults.

Because of internal math in the FM-3 and FM-4, some user unit combinations may cause module or drive trajectory faults. The maximum motor velocity allowed by the drive is detailed under the distance section of the User Units View and is labeled “User Unit Limited Speed”. When the user unit setup is altered in such a way that the maximum motor speed allowed by the drive is less than the maximum speed allowed by the chosen motor, the readout of maximum motor speed allowed by the drive changes to have a red background. If a configuration is downloaded to the FM-3/4 with a red background on the “User Unit Limited Speed”, the drive will obtain a trajectory fault at speeds near this velocity. To alleviate this issue, simply remove decimal places from your user units, and/or change the characteristic distance (numerator) of your scaling parameters to be a smaller number that it was. The red background indicating module trajectory faults will go away when the user unit setup is scaled for a realistic accuracy based on the encoder counts per revolution.

Velocity Group

Enable Separate Distance Units Check Box

If checked, separate distance and velocity units, name and scaling will be enabled. If not enabled, the velocity units, name and scaling will be defined by the Distance Group.

Scaled Distance Name

If the user wants the velocity units to have a different distance scaling than the distance units a name can be entered here up to 10 characters. For example, the user distance units could be inches while the velocity units are feet per minute.

Velocity Distance Units Scale Factor

This parameter scales the Velocity Distance Units back to actual distance units. To do this, enter the number of distance user units that are equal to one velocity scaled distance unit.

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