Detailed operation by function groups
280
6.8.5 Encoder error detection
If the encoder is disconnected or there is a connection error when “Detection of
encoder error” at PRT-09 is set to “Yes”, the inverter detects the encoder error.
For open-collector encoders, set PRT-09 to “No” as encoder error detection is
not available for this type of encoders.
If electronic interference distorts the encoder’s input wave, adjust the “Encoder
LPF time constant” setting at PRT-10 to reduce the distortion.
When the encoder settings are not accurate, normal speed control does not
work. And the inverter frequently generates trips such as “over current” or “over
voltage”. If this happens, refer to
Code
Keypad display Name
Range
Unit
Default setting
PRT_09
Enc Err Chk
Detection of encoder error
0 (No)
1 (Yes)
1 (Yes)
PRT_10
Enc LPF
Encoder LPF time constant 0–100
ms
1
6.8.6 Software encoder error detection (PRT_11–12:
Detection time of encoder error, encoder error
based on the speed rate)
Accurate motor speed detection is critical for motor speed control when an
encoder is installed. Correct encoder connection and motor connection are
required to ensure accurate speed control. If the motor operation is maintained
even after input signal errors such as an encoder disconnection occurred, or if
the motor is operated while the encoder or motor cables are incorrectly
connected, the motor may not operate properly. Also, the resultant high current
flow may result in motor damage. It is essential to ensure that encoder error and
connection problems are closely monitored.
The L100 inverter detects encoder error with hardware diagnosis (when PRT_09
is set to “Yes”). This is for checking the status of encoder pulse input (input
pulse) to detect the hardware damage by some reason such as a disconnection
of encoder. However, error of connection cannot be detected only with hardware
diagnosis. Set PAR_31 to "Rotational" and perform an encoder test when