Mitsubishi Electric FR-F740 EC Instruction Manual page 279

Parameter
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 de-
tection signals (FU, FU2) may repeat ON/OFF (chatters). Setting hysteresis to the detected fre-
quency prevents chattering of these signals.
Fig. 6-69:
NOTES
Setting a higher value to this parameter slows the response of frequency detection signals
(SU, FU and FU2).
The output frequency compared with the set frequency changes depending on the control
system. During V/f control the output frequency and during simple flux magnetic vector con-
trol the output frequency before slip compensation is compared with the set frequency.
When terminal assignment is changed using Pr. 190 to Pr. 196 "Output terminal function
selection", the other functions may be affected. Please make setting after confirming the
function of each terminal.
FR-F700 EC
Output frequency [Hz]
Pr. 42
OFF ON
FU
Example of output frequency detection signal (FU)
Function assignment of external terminals
ON ON OFF
Pr. 870
I002302E
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