Difference between S-ON and FREE inputs

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Difference between S-ON and FREE inputs

Post by om_tech_support_JT » Fri May 31, 2013 10:03 am

Q: On the NX series servo drivers, the S-ON input and FREE input both turn the motor current off, but both also clear the position counter. What is the difference between the FREE input and the S-ON input (in position control mode)?

A: The S-ON input is used to turn the motor current on so the motor will have excitation. In order for the motor to rotate, the S-ON input has to be ON before pulses are input to its driver. The FREE input can be used to turn the current ON or OFF to manually position the motor shaft whenever needed. The FREE input will override the S-ON input.

FREE input
When the FREE input is turned ON, the motor current will be cut off. The motor will lose its holding torque, and the output shaft can be turned with an external force. The deviation counter will also be cleared.
If the FREE input is turned ON while the position is held with the electromagnetic brake, the electromagnetic brake will be released. Accordingly, the position can no longer be held.

S-ON input
Turning the S-ON input ON will excite the motor. In the case of an electromagnetic brake motor, the electromagnetic brake will be released after the motor is excited. When the S-ON input is OFF, the deviation counter will be cleared and input operation commands will be ignored.

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