Chapter 9 Inverter Functions
9-13-4
9.13.4 Outputting a Signal When the Output Frequency is Close to 0 Hz
 How to detect and tell the system that the output frequency to the motor is close to 0 Hz?
 Assigning "Zero speed detection [ZS] (21)" to one of the output terminal functions
([C021]/[C022]/[C026]) enables the inverter to output 0 Hz detection signal.
 When the output frequency of the inverter drops below the level set with "Zero speed detection
level [C063]", [ZS] is output.
 During 0 Hz operation, such as when the inverter is stopped or during DC braking, [ZS] is on
because the frequency is 0 Hz.
 When encoder feedback is used, this signal is output by determining the actual rotation speed
of the motor.
Zero speed detection [ZS]:
The output frequency outputs the
analog disconnection signal