134
Function assignment of external
terminal and control
(3) Speed detection hysteresis (Pr. 870)
⋅This function prevents chattering of the speed detection
signals.
When an output frequency fluctuates, the up to frequency
signal (SU) and output frequency detection signals (FU,
FU2) may repeat ON/OFF (chatters). Setting hysteresis
to the detected frequency prevents chattering of these
signals.
REMARKS
The output frequency compared with the set frequency changes depending on the control met hod.
CAUTION
⋅Changing the terminal assignment using Pr. 190 to Pr. 196 (output terminal function selection) may affect the other functions.
Please set parameters after confirming the function of each terminal.
♦ Parameters referred to ♦
Pr. 190 to Pr. 196 (output terminal function selection) Refer to page 128
Pr.87
0
Pr.42
Output frequency
(Hz)
ON
ON
ON
FU
Example of output frequency detection signal (FU)
OFF OFF
REMARKS
Setting a higher value to this parameter slows the response of
frequency detection signals (SU, FU and FU2).
Control Method Compared Output Frequency
V/F control Output frequency
Simple magnetic flux vector control Output frequency before slip compe nsation