Changing the Voltage Output on a NI Motion Controller for Drives That Do Not Accept ±10 V

By default, the NI motion controller is set up to output a command signal in the range of ±10 V, which is accepted by most servo drives. For drives that require a different command voltage range, adjust the torque limit (voltage limit) of the controller either by using the Load Torque Limit function/VI, or by changing the Torque Limits and Offset in the Trajectory Parameters when you are tuning your motor. For example, if you have a drive that requires a signal of ±5 V, change the output voltage of the controller to the drive by adjusting the torque limit to ±5 V. For information about using the Load Torque Limit function, refer to the NI-Motion VI or Function Help. As described in the description for flex_load_torque_lim, the range for the torque limits is
-32,768 to +32,767, which corresponds to ±10 V. If you change this range to -16,384 to +16,383, the voltage range will be ±5 V.

The same result can be achieved by setting the torque limits in Measurement and Automation explorer under the Axis Settings»Miscellaneous Tab, then pressing Apply and Initialize.



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When you adjust your voltage range by adjusting the torque limits, the resolution of your command signal is reduced as well. For example, if you adjust the voltage output from ±10 V to ±5 V, the resolution of the command signal changes from ±32,768 to ±16,384.

Related Links:
NI-Motion Function Help
NI-Motion VI Help

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