Encoder errors – Hitachi SJ300 Series User Manual
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Chapter 2 – Explanation of Functions
2.8 Encoder
Errors
If the signal from encoder doesn’t correspond to the inverter output for any reason, then the inverter
displays a trip event.
1. Speed deviation error
Inverter enters the trip state when a speed deviation is detected due to abnormal signal from encoder
or abnormal shaft speed caused by the load. For inverter to record a trip event, the speed difference
between reference and actual motor speed must be more than the threshold for 200ms. The threshold
for speed deviation (P027) is configurable. An output signal for excess speed deviation (22: [DSE])
can be assigned to an intelligent output terminal for use by an external controller or other device.
Speed overshoot due to the inertia of the load can also trigger this function.
This function can be disabled with parameter P051.
Error display (Speed deviation)
OPE-S: E63.X or E73.X
SRW: OP1-3 or OP2-3
2. Motor rotational direction error
When the encoder is connected with A and B phases reversed and the motor turns in a wrong
direction, the inverter records a trip event. In other words, if a forward (reverse) rotation is commanded
but the feedback signal from the encoder indicates reverse (forward) rotation for 200ms, then the
inverter will trip. The motor rotational direction signal (27: DRN) can be assigned to an intelligent
output terminal for use by an external controller or other device.
Motor rotational direction error can also be triggered by reverse torque bias or the car slipping upward
or downward on brake release.
This function can be disabled by parameter P051.
Error display (Motor rotational direction)
OPE-S: E64.X or E74.X
SRW: OP1-4 or OP2-4
Function
Code
Function Name
Setting Range
Remarks
P027
Threshold to detect
speed deviation error
0.00-99.99/100.0-120.0(Hz)
P050
Encoder disorder
trip selection
(Speed deviation)
－
00: OFF, 01: ON
P051
Encoder disorder
trip selection
(Motor rotational direction)
－
00: OFF, 01: ON
C021 -
C026
Intelligent output terminal
1 - 5
－
22: DSE, 27: DRN
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