Mitsubishi Electronics FR-A700 ユーザーズマニュアル

(3) Low speed detection (LS signal, Pr. 865)

⋅ The low speed detection signal (LS) is output when the

output frequency drops below the Pr. 865  Low speed
detection setting.

⋅ When speed control is performed by Real sensorless

vector control or vector control, a fault (E.OLT) is
displayed and the inverter trips if frequency drops to the
Pr. 865 setting by torque limit operation and the output
torque exceeds Pr. 874 OLT level setting and remains for
more than 3s.

⋅ For the LS signal, set "34 (positive logic) or 134 (negative

logic)" in Pr. 190 to Pr. 196 (output terminal function
selection) and assign functions to the output terminal. 

⋅

The FU signal is assigned to the terminal FU and the SU signal is assigned to the terminal SU in the initial setting.

⋅

All signals are OFF during DC injection brake, pre-excitation (zero speed control, servo lock), or start time tuning.

⋅ The type of frequency (output as the following signals), which is compared with the set frequency, differs by the

control method. 

 

⋅ When terminal assignment is changed using Pr. 190 to Pr. 196 (output terminal function selection), the other functions may be

affected. Set parameters after confirming the function of each terminal.

♦ Parameters referred to ♦

ON

LS

ON

OFF

Output frequency 

(Hz)

Time

V/F control

Output frequency

Output frequency

Advanced magnetic 

flux vector control

Output frequency before the slip compensation. 

Output frequency before the slip compensation. 

Real sensorless 

vector control

Frequency command

Estimated frequency (estimated from the actual 

motor speed)

Encoder feedback 

control

Actual motor speed converted as frequency

Actual motor speed converted as frequency

Vector control

Frequency command

Actual motor speed converted as frequency