Control Techniques FM-3 Reference Manual page 201

Figure 117: User Units View
Now set up the parameters in the Distance group on the User Units view. The Tab key is used to easily jump through the
available parameters. After entering data in a field, press the Tab key to move to the next parameter. The parameters you
must fill out are as follows:
Units Name – Enter the character string you wish to use for your distance units.
Decimal Places – Enter the number of digits after the decimal place you wish to use in all distance parameters throughout
the software (i.e. index distances/positions, PLS On/Off points). Use the Up/down arrows to increase or decrease the number
of digits.
Distance Units Scaling – Enter the number of User Units the motor/load travels for each revolution of the motor. You must
enter the numerator and the denominator for this scaling factor.
Note
User Units may affect end motor speed and could cause trajectory faults.
Because of internal math in the FM-3, 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 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 the user units, and/or change the characteristic distance (numerator) of the scaling parameters to be a
smaller number. 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.
Master Units View
Use this view to setup parameters for synchronized motion.
Position View
The Settings group on this view sets the Define Home Position.
Quick Start
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