Mitsubishi Electric FR-A800 Series Instruction Manual page 487

• To use the LS signal, set "34 (positive logic) or 134 (negative logic)" in any of Pr.190 to Pr.196 (Output terminal function
selection) to assign the function to the output terminal.
Pr.865
LS ON
 Speed detection hysteresis (Pr.870)
Setting the hysteresis width for the detected frequency prevents chattering of the Speed detection (FB) signal. When an output
frequency fluctuates, the following signals may chatter (turns ON and OFF repeatedly).
• Up to frequency (SU) signal
• Speed detection (FB, FB2, FB3) signals
• Low speed detection (LS) signal
Setting hysteresis to the detected frequency prevents chattering of these signals.
Output
frequency
(Hz)
Pr.42
FB
ON
Example of the speed detection (FB) signal
NOTE
• In the initial setting, the FU signal is assigned to terminal FU, and the SU signal is assigned to terminal SU.
• All signals shown in the following table are OFF during the DC injection brake operation, during the pre-excitation (zero speed
control or servo lock) operation, and during tuning at start-up.
• The reference frequency in comparison with the set frequency differs depending on the control method.
• Setting a higher value in Pr.870 causes a lower responsivity of the signals for frequency detection (SU, FB, FB2, FB3, and LS
signals).
• The logic (ON/OFF switching) of the LS signal is the reverse of that of the FB signal.
• 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
Pr.874 OLT level settingpage 245
486
5. PARAMETERS
5.11 (M) Item and output signal for monitoring
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OFF ON
ON
ON
Control method or function
V/F control
Advanced magnetic flux vector
control
Real sensorless vector control
Encoder feedback control
Vector control
PM sensorless vector control
selection)page 473
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Time
Output frequency
(Hz)
Pr.870
SU output level
Pr.870
Pr.41
Set frequency
Pr.870
Pr.870 SU output level
Pr.870
SU signal
Example of the up to frequency (SU) signal
FU, FU2, FU3
Output frequency
Output frequency before the slip
compensation
Frequency command value
Frequency converted from actual
motor speed
Frequency command value
Frequency command value
ON ON
Reference frequency
FB, FB2, FB3, SU, LS
Output frequency
Output frequency before the slip
compensation
Estimated frequency (actual motor
speed)
Frequency converted from actual motor
speed
Frequency converted from actual motor
speed
Estimated frequency (actual motor
speed)
Time
ON