Mitsubishi FR-E800 Variable Frequency Drive
55 fault codes documented
Continuous operation during communication fault
This warning appears when the inverter continues to operate despite an error detected in the communication line or communication option, specifically when Pr.502 is set to '6'. It indicates an ongoing communication problem that, while not immediately stopping the inverter, requires attention.
Duplicate IP address
This warning appears when the inverter detects that its assigned IP address is already in use by another device on the network. This conflict prevents proper network communication and can cause system instability.
Option Fault / Internal Contact Failure
The inverter output is shut off due to a contact failure between the inverter and a plug-in option, or if a manufacturer setting switch on the plug-in option has been altered. Excessive electrical noise around the inverter can also contribute to this fault. This compromises the functionality of the plug-in option.
Inverter Output Fault / Earth Fault
The inverter has detected an output current fault, specifically an earth (ground) fault, on its output side (affecting the motor or connection cable). This indicates a breakdown in insulation, leading to current leakage to ground. An earth fault is a significant safety hazard and can cause severe damage to the motor or inverter if unresolved.
Opposite Rotation Deceleration Fault
During torque control under Real sensorless vector control, if the speed command and estimated speed directions differ when reversing, the motor may not decelerate correctly at low speeds. This leads to an overload condition, shutting off the inverter output. This protective function is specific to Real sensorless vector control and prevents motor overcurrents.
Internal Circuit Fault
This fault indicates a general malfunction within the inverter's internal circuitry. The specific cause is not detailed in the manual, suggesting a fundamental hardware problem that cannot be resolved through basic troubleshooting. Continued attempts to operate with this fault may lead to further damage.
User-Defined PLC Function Error
The inverter output is shut off because a user-defined protective function, configured via the PLC function, has been activated. This occurs when a value between "16" and "20" is written to the special register SD1214 while the PLC function is enabled (Pr.414 is not "0"). It signifies a condition that the user's PLC program has flagged as a fault.
Analog Input Fault
The inverter output is shut off if an incorrect signal type or magnitude (e.g., 30mA+ current or 7.5V+ voltage) was detected on terminal 2 or 4, contrary to the parameter settings for current input. This indicates a mismatch between the physical input signal and the configured analog input type.
Brake transistor err
The inverter output is shut off due to a fault in the brake circuit, typically indicating damage to the brake transistor. This is a critical internal hardware fault requiring immediate attention to prevent further damage.
Abnormal Output Current Detection
The inverter output has been shut off because the output current exceeded the threshold set in Pr.150 Output current detection level. This protective function is only active when Pr.167 Output current detection operation selection is set to "1". It indicates an overcurrent condition that is monitored independently of the main overcurrent trip.
Board Combination Fault
This fault indicates that the installed circuit board is either incompatible with the specific inverter model or is not correctly seated/connected within the inverter. The inverter will cease operation to prevent potential damage. An incorrect or improperly connected board can lead to system malfunction or inability to perform intended functions.
CPU Fault
The inverter output is shut off due to a communication fault within the built-in CPU, potentially indicated by specific sub-faults (E.5, E.6, E.7 on FR-LU08). This can be triggered by excessive electrical noise in the environment or an improper connection of an Ethernet communication cable. An internal CPU fault can render the inverter inoperable.
Ethernet Communication Fault
This fault indicates an interruption in Ethernet communication, often due to physical factors, when signal loss detection (Pr.1431 or Pr.1457 = '3') is enabled. The inverter output shuts off if communication is broken for the time set in Pr.1432. It can also occur in CC-Link IE Field Network Basic if data isn't received or the cyclic transmission status bit turns OFF, or in BACnet/IP if conflicting IP addresses are detected. A communication fault can stop critical processes and lead to loss of control over the inverter.
Heatsink Overheat
This fault indicates that the inverter's internal heat sink has exceeded its safe operating temperature, triggering a temperature sensor and shutting down the inverter output. This usually happens when the ambient temperature is too high, the heat sink is blocked by debris, or the cooling fan is not functioning correctly. Sustained overheating shortens the lifespan of inverter components and can lead to permanent damage.
Ground Fault
The inverter output is shut off if an earth (ground) fault overcurrent flows on the inverter's output side (motor/load side). This protective shutdown prevents electrical hazards, motor damage, and further system failures due to insulation breakdown.
Input Phase Loss
This fault occurs when Pr.872 (Input phase loss protection selection) is enabled ('1') and one of the three phases of the input power supply to a three-phase model inverter is lost. The inverter immediately shuts off its output to prevent damage. This condition indicates a break, loose connection, or failure in one of the incoming power lines. Continued operation with a phase loss can lead to severe damage to the inverter's input rectifier bridge.
Inrush Current Limit Circuit Overheat
The inverter output is shut off when the resistor in the inrush current limit circuit has overheated, indicating a fault within this circuit. This typically results from frequent power ON/OFF cycles or a damaged component within the inrush current path. Continued operation with this fault risks further component damage.
Lower limit fault
The inverter output is shut off when the load on the motor falls below the defined lower limit fault detection range. This protective function detects abnormally light load conditions, potentially indicating a mechanical issue or a disconnected load, and is active only when Pr.1491 is not '9999'.
Output phase loss
The inverter output is shut off if one of the three phases (U, V, W) on the output side (motor/load side) is lost. This typically indicates a broken wire, loose connection, or open circuit in the motor wiring, leading to unbalanced currents and potential motor overheating.
Upper limit fault
The inverter output is shut off when the load on the motor exceeds the defined upper limit fault detection range. This is a protective function to prevent damage from excessive loading, active only when Pr.1490 is not set to '9999'.
Overcurrent During Acceleration
When the inverter's output current rapidly increases to approximately 230% of the rated current during the acceleration phase, the internal protection circuit is triggered, leading to an immediate shutdown of the inverter output. This can indicate excessive load, improper acceleration settings, or an output short-circuit condition. Left unaddressed, this can cause repeated trips, motor damage, or inverter component stress.
Overcurrent During Constant Speed
This fault occurs when the inverter's output current reaches or exceeds approximately 230% of the rated current while operating at a constant speed. This activates the protection circuit, causing the inverter output to shut down. Common causes include sudden load changes, output short-circuits, or incorrect control parameters. Repeated overcurrent can lead to motor and inverter damage.
Overcurrent during Deceleration
The inverter output current has exceeded approximately 230% of its rated value during deceleration, causing the protection circuit to activate and shut off the inverter. This can be caused by sudden speed reductions, an output short-circuit, or issues with the mechanical brake. Unresolved, it can lead to component stress and potential damage.
Ext TH relay oper
The inverter output is shut off because an external thermal relay (for motor overheat protection) or an internally mounted motor thermal relay has activated (contacts open). This protective shutdown prevents motor damage from excessive temperature, and is active when '7' (OH signal) is assigned to Pr.178-Pr.184.
Stall prevention STP
The inverter output is shut off if stall prevention operation causes the output frequency to drop to 0.5 Hz for 3 seconds, or if torque limit operation causes frequency to drop to Pr.865 and output torque exceeds Pr.874 for 3 seconds in speed control. This protective fault indicates severe motor overload or an issue with stall prevention settings.
Communication Option Fault
The inverter output is shut off due to a communication line error in the installed communication option. This can stem from incorrect option settings, a loose plug-in option card, or a damaged communication cable, including improper termination. Loss of communication functionality can disrupt system control.
Option Fault
This fault appears under several conditions: if a plug-in option for torque command is selected (Pr.804) but no option is mounted, if a manufacturer setting switch on a plug-in option is changed, or if a communication option is connected while Pr.296 (Password lock level) is set to '0' or '100'. It indicates an incorrect configuration or an issue with an installed option.
Overspeed Occurrence
The motor speed has exceeded the configured Pr.374 Overspeed detection level under encoder feedback, Real sensorless vector, Vector, or PM sensorless vector control, leading to an inverter shutdown. This protective function prevents mechanical damage from excessive speed.
Speed Deviation Excess Detection
The inverter output is shut off because the motor speed significantly deviated from the command value during Vector or PM sensorless vector control, preventing proper control. This usually occurs when Pr.285 Speed deviation excess detection frequency is active and can be caused by sudden load changes or incorrect parameter settings. Prolonged deviation can lead to unstable operation.
Regenerative Overvoltage during Acceleration
Regenerative power or a power supply surge has caused the inverter's internal main circuit DC voltage to rise above the specified limit, triggering the protective shutdown. This can occur with rapid acceleration, especially with vertical loads, or if stall prevention settings are incorrect. Continued overvoltage can damage inverter components.
Parameter Storage Device Fault (Control Circuit Board)
A fault has occurred in the inverter's parameter storage (EEPROM failure) on the control circuit board, causing the inverter output to shut off. This often results from an excessively high number of write operations to the EEPROM, leading to degradation. This fault indicates a potential hardware degradation that can affect parameter retention.
Parameter Storage Device Fault (Main Circuit Board)
A critical fault has occurred in the inverter's main circuit board, specifically related to the storage of inverter model information. This indicates an internal memory corruption or hardware failure which prevents the inverter from identifying itself or its configuration. This is a severe internal fault requiring factory attention.
PID Signal Fault
The inverter output is shut off if, during PID control, the measured feedback value goes outside the limits set by Pr.131 (PID upper limit) or Pr.132 (PID lower limit), or if the absolute deviation from the setpoint exceeds Pr.553 (PID deviation limit). This protective function is not active by default and must be enabled via Pr.554. An erroneous PID signal can lead to unstable process control or unexpected shutdowns, indicating a sensor issue or incorrect parameter tuning.
PU Disconnection / RS-485 Communication Fault
The inverter output is shut off because communication between the inverter and the Parameter Unit (PU) has been suspended, or RS-485 communication errors exceeded the retry count or check time. This occurs when Pr.75 has PU disconnection detection enabled, or if Pr.121 or Pr.122 settings for RS-485 communication are exceeded. It indicates a loss of control or monitoring via the PU/RS-485 link.
Retry Count Excess
The inverter output is shut off because an automatic fault recovery attempt (retry) failed to resolve a preceding fault within the number of retries configured in Pr.67 Number of retries at fault occurrence. This means the underlying problem persists despite multiple attempts to restart, preventing the inverter from resuming normal operation.
Safety Circuit Fault
The inverter output has been shut off due to a detected fault in the safety circuit or a functional safety-related issue. This can be caused by a broken wire in the safety input terminals (S1, S2, PC) when using safety functions, or general functional safety failures in Safety Communication models. This critical fault ensures machinery cannot operate unsafely.
Motor Step Out
The inverter output is shut off when the motor loses synchronization during operation, a condition specifically monitored under PM sensorless vector control. This fault indicates a loss of control over the motor's rotor position, leading to erratic operation.
Motor Overload Trip (Electronic Thermal Relay Function)
The inverter's electronic thermal O/L relay function detects when the motor is overheating due to excessive load or insufficient cooling, especially during low-speed operation. A pre-alarm (TH) is issued at 85% of the Pr.9 setting, and the inverter output stops when the accumulated heat reaches the trip level. This protection may be insufficient for multiple or special motors, requiring an external thermal relay. Overheating can severely damage the motor windings.
USB Communication Fault
The inverter output has shut off because USB communication was interrupted for a duration exceeding the time set in Pr.548 USB communication check time interval. This indicates a break in the USB connection or an incorrectly configured communication watchdog timer. Loss of communication will prevent external control and monitoring.
Undervoltage
This protective function activates, particularly with PM motors, when the converter voltage drops due to power supply issues like power failure or voltage sags. This causes the motor to coast, and if an automatic restart function is enabled, it may lead to repeated restarting and coasting cycles. Insufficient input voltage can prevent the inverter from maintaining stable operation and delivering rated power, potentially leading to inconsistent process control.
Ethernet communication fault
This fault appears when Ethernet communication is interrupted by physical factors, especially when Pr.1431 (Ethernet signal loss detection function selection) is set to a value between '1' and '3'. It signifies a physical layer problem with the Ethernet connection to the inverter.
Write disable error
This error occurs if a parameter setting was attempted while Pr.77 (Parameter write selection) disables write operations, if frequency jump ranges (Pr.31 to Pr.36) overlap, or if communication between the PU (Parameter Unit) and the inverter is abnormal. It indicates an issue preventing parameter modification or a communication problem.
Write error during operation
This error signifies that a parameter write was attempted while Pr.77 (Parameter write selection) was set to '0', which explicitly disables parameter write operations during inverter run-time. It prevents accidental or unauthorized parameter changes while the system is active.
Calibration error
This error indicates that the analog input bias and gain calibration values (specifically C3, C4, C6, and C7) have been set too close to each other. This can lead to inaccurate analog signal processing and incorrect inverter behavior.
Mode designation error
This error occurs if parameter setting was attempted in External or NET operation mode while Pr.77 (Parameter write selection) is '1', or if parameter write was attempted when the command source is not the operation panel. It indicates a conflict between the current operating mode or command source and the attempt to write parameters.
Operation panel lock
The operation panel is in a locked state, disabling all operations except pressing the STOP/RESET key. This feature is typically used to prevent unintended changes to inverter operation parameters or commands.
IP address fault
This warning appears when the configured IP address or subnet mask for the inverter falls outside the specified valid range. This indicates an invalid network configuration that will prevent the inverter from communicating correctly on the network.
Load fault warning
This warning appears when the current load on the inverter deviates from the detection width defined by Pr.1488 (Upper limit warning detection width) or Pr.1489 (Lower limit warning detection width). It indicates an unexpected load condition, either too heavy or too light, potentially due to equipment issues.
Password locked
The password function is active, restricting the display and setting of parameters. This security feature prevents unauthorized access and modification of the inverter's configuration.
Maintenance timer
This indicator appears when the inverter's cumulative energization time reaches or exceeds the value set in parameter Pr.504. It serves as a reminder that routine maintenance may be due for the equipment.
PU stop
This indication means the motor has been stopped either by pressing the STOP/RESET key (when enabled in modes other than PU operation via Pr.75) or by the emergency stop function. It signifies a deliberate or emergency shutdown of the motor's operation.
Regenerative brake pre-alarm
This pre-alarm appears if the regenerative brake duty reaches or exceeds 85% of the value set in Pr.70 (Special regenerative brake duty). It's a warning that the regenerative braking capacity is nearing its limit, and a regenerative overvoltage (E.OV[]) fault may occur if it reaches 100%.
Safety stop
This alarm appears when the safety stop function is activated, resulting in the shutoff of the inverter's output. It signifies a protective measure triggered by an emergency stop device or a disconnection within the safety circuit.
Speed limit indication (output during speed limit)
This indicator appears if the speed limit level is exceeded during torque control. It signifies that the inverter is actively limiting the motor speed to the set maximum, preventing it from overrunning.
Electronic thermal relay function pre-alarm
This pre-alarm appears if the cumulative value of the electronic thermal O/L relay reaches or exceeds 85% of the preset level in Pr.9 (Electronic thermal O/L relay). It serves as a warning that the motor is approaching its thermal limit, and a protective shutdown will activate if 100% is reached.