Mitsubishi Electric FR-F820-00046, Instruction Manual

Page: 415 / 940

Parameters (M) Monitor display and monitor output signal
FR-F800 5 - 243
Speed detection hysteresis (Pr. 870)
This function prevents chattering of the speed detection signals. When an output frequency fluctu-
ates, the up to frequency signal (SU) and the speed detection signals (FB and FB2) may repeat ON/OFF
(chatter).
Setting hysteresis to the detected frequency prevents chattering of these signals.
Fig. 5-99:
Example of the speed detection (FB) signal
I002629E
I003032E
Fig. 5-100: Example of the up to frequency (SU) signal
NOTES In the initial setting, the FU signal is assigned to the terminal FU, and the SU signal is assigned to
the terminal SU.
All signals turn OFF during DC injection brake, and tuning at start-up.
Each signal's reference frequency differs by the control method.
Setting a higher value in Pr. 870 slows the response of frequency detection signals (SU, FB, FB2).
Changing the terminal assignment using Pr. 190 to Pr. 196 (output terminal function selection)
may affect the other functions. Set parameters after confirming the function of each terminal.
Parameters referred to
Pr. 190 to Pr. 196 (output terminal function selection) => page 5-231
FB
Pr. 42
OFF OFF
ON
ON
ON
Output
frequency
(Hz)
Pr. 870
Pr. 41
Time
Output
frequency
(Hz)
SU output level
Set frequency
SU output level
SU signal
Pr. 870
Pr. 870
Pr. 870
Pr. 870
ON ON ON
Control method
Compared frequency
FU, FU2 FB, FB2, SU
V/F control Output frequency Output frequency
Advanced magnetic flux vector
control Output frequency before the slip
compensation Output frequency before the slip
compensation
PM motor control Frequency command value
Estimated frequency (actual motor
speed)