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Frequently Asked Questions
FAQ: SMD34E2 Removing Main Power
The AMCI SMD34E2 integrated stepper motor driver has Main and Auxiliary terminals on its power
connector. The Main supplies power to both the motor and to the electronics while the optional
Auxiliary supplies power only to the electronics, including the network connection and the encoder.
It is a common practice to connect power to both the Main and Auxiliary Power pins and to remove
the Main Power as part of a safety system. The Auxiliary Power maintains the network connection
while the Main Power is removed.
Removing the Main Power will cause the following to occur.
•
The Driver Fault Status bit will be set
•
The Position Invalid Status bit will be set
•
The Driver Enabled Status bit will be reset
The following three rungs show the action that you should take while the Main Power is removed and
the steps needed to recover after the Main Power has been restored.
While the Main Power is removed, write a word of 0 to Output Word 0, which is also called
Command Word 0. This will prepare the SMD34E2 to accept the next command after the
Main Power has been restored.
After the Main Power has been restored, and if there is a Driver Fault, send the Reset Error
command to the SMD34E2.
This command will also enable the driver causing it to send power to the motor.
