Mitsubishi Electric 700 Series, Instruction Manual

Page: 145 / 416

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 method.
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.870
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 compensation