Mitsubishi Electric FR-D720S SC EC Instruction Manual page 256

Function assignment of external terminals
Zero current detection (Y13, Pr. 152, Pr. 153)
If the output current remains lower than the Pr. 152 setting during inverter operation for longer
than the time set in Pr. 153, the zero current detection (Y13) signal is output from the inverter's
open collector or relay output terminal. As soon as the signal is output to terminal Y13, it remains
turned on for 100ms.
When the inverter's output current falls to "0", torque will not be generated. This may cause a
drop due to gravity when the inverter is used in vertical lift application. To prevent this, the output
current zero signal (Y13) can be output from the inverter to close the mechanical brake when the
output current has fallen to "zero".
Set "13" (source logic) or "113" (sink logic) to any of Pr. 190, Pr. 192 or Pr. 197 to assign the func-
tion of the output power detection signal (Y13) to the output terminal.
Fig. 6-56: Zero current detection
NOTES This function is also valid during execution of the online auto tuning.
The response time of Y12 and Y13 signals is approximately 0.1s. Note that the response
time changes according to the loadcondition.
When Pr. 152 = "0", detection is disabled.
Changing the terminal assignment using of Pr. 190, Pr. 192 or Pr. 197 may affect the other
functions. Make setting after confirming the function of each terminal.
b
CAUTION:
The zero current detection level setting should not be too high, and the zero current
detection time setting not too long. Otherwise, the detection signal may not be output
when torque is not generated at a low output current.
To prevent the machine and equipment from resulting in hazardous conditions by use
of the zero current detection signal, install a safety backup such as an emergency
brake.
6 - 106
Output current
Pr. 152
Start signal
Zero current
detection signal Y13
Pr. 152
100ms
ON
ON
Pr. 153
Parameter
Time
ON
Pr. 153
I001156E