Mitsubishi Electric FR-A800 Series Instruction Manual page 486

 Output frequency detection (FU, FU2, FU3 signals, FB, FB2, FB3 signals,
Pr.42, Pr.43, Pr.50, Pr.116)
• The Output frequency detection (FU) signal and the Speed detection (FB) signal are output when the output frequency
reaches or exceeds the Pr.42 setting.
• The FU, FU2, and FU3 signals are useful for applying or releasing electromagnetic brake, etc.
• The FU, FU2, and FU3 signal is output when the output frequency (frequency command) reaches the set frequency. On
the other hand, the FB, FB2, and FB3 signal is output when the detected actual speed (estimated speed under Real
sensorless vector control, or feedback value under Vector control) of the motor reaches the set frequency. The FU signal
and the FB signal are output at the same manner under V/F control or Advanced magnetic flux vector control or during the
encoder feedback control operation.
• The frequency detection dedicated to motor rotation in reverse direction is enabled by setting the frequency in Pr.43. This
setting is useful when the timing of the electromagnetic braking during forward rotation operation (for example, during lifting
up in the lifts operation) is different from that during reverse rotation operation (lifting down).
• When Pr.43 ≠ "9999", the Pr.42 setting is for the forward rotation operation and the Pr.43 setting is for the reverse rotation
operation.
• When a different detection point of the frequency is required, Pr.50 and Pr.116 are available. The FU2 (or FB2) signal can
be set to be output when the output frequency reaches the Pr.50 setting or higher, and the FU3 (or FB3) signal can be set
to be output when the output frequency reaches the Pr.116 setting or higher.
(Hz)
Output
signal
FU/FB OFF
FU2/FB2 OFF
FU3/FB3 OFF
• To use each signal, set the corresponding number selected from the following table in any of Pr.190 to Pr.196 (Output
terminal function selection) to assign the function to an output terminal.
Output signal
FU
FB
FU2
FB2
FU3
FB3
 Low speed detection (LS signal, Pr.865)
• When the output frequency drops to the setting of Pr.865 Low speed detection or lower, the Low speed detection (LS)
signal is output.
• In the speed control mode under Real sensorless vector control, Vector control, or PM sensorless vector control, the fault
occurs, the indication "E.OLT" appears, and the inverter output power shuts off if the inverter condition that the output
frequency drops to the Pr.865 setting and the output torque exceeds the setting of Pr.874 OLT level setting by torque
limit operation continues for 3 seconds or longer.
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Forward
rotation
Pr.116
Pr.50
Pr.42
ON OFF
ON OFF
ON OFF
Pr.190 to Pr.196 settings
Positive logic Negative logic
4 104
41 141
5 105
42 142
6 106
43 143
search engine
Pr.43
Time
Pr.50
Pr.116
Reverse
rotation
ON OFF
ON OFF
ON OFF
Related
Parameter
42, 43
50
116
5. PARAMETERS
5.11 (M) Item and output signal for monitoring
1
2
3
4
5
6
7
8
9
10
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