Error, fault and alarm codes of products - what each code means, its causes and what to do - read from the manufacturers’ manuals, with the manual page each answer comes from.
Error excessive occurs when acceleration/deceleration time is too short, torque limit is too low, or motor fails to start due to voltage drop. The manual's first action is: “Power OFF→ON”
Command pulse frequency alarm occurs when pulse frequency is too high, noise interferes with pulses, or the command device has failed. The manual's first action is: “Power OFF→ON”
Overspeed alarm indicates command pulse frequency exceeds permissible limits, acceleration/deceleration time constants are too small, or system instability causes overshoot. The manual's first action is: “Power OFF→ON”
Overcurrent alarm occurs from short circuits in servo amplifier output phases, faulty transistors (TPM), or ground faults on output phases. The manual's first action is: “Power OFF→ON”
Main circuit error happens if power and motor wires are shorted at TE1, motor cable sheaths deteriorated causing ground fault, or main circuit failure in amplifier. The manual's first action is: “Power OFF→ON”
Overload 2 occurs due to machine collision, incorrect motor terminal connections, or unstable servo operation causing hunting. The manual's first action is: “Power OFF→ON”
Overload 1 indicates servo amplifier output current exceeded continuous limits, system instability, or machine collision. The manual's first action is: “Power OFF→ON”
Servo motor overheat occurs when ambient temperature exceeds 40°C, motor is overloaded, or encoder thermal sensor fails. The manual's first action is: “Power OFF→ON”
Main circuit device alarm indicates servo amplifier fault, continuous power cycling under overload, or fan failure in the servo amplifier. The manual's first action is: “Power OFF→ON”
Undervoltage occurs when supply voltage drops below 160VAC (or 83VAC for MR-J2S-□A1), or if a prolonged control power failure occurred. The manual's first action is: “Power OFF→ON”
Overvoltage alarm indicates voltage exceeds limits, possibly due to incorrect regenerative brake settings or lack of regenerative brake option. The manual's first action is: “Flickers at occurrence of the alarm.”
Regenerative error happens if parameter No. 0 is misconfigured, regenerative brake resistor or option not connected, or excessive regenerative power is applied. The manual's first action is: “Power OFF→ON”
Serial communication error occurs from faulty cables (open/short), or a malfunctioning communication device like a PC. The manual's first action is: “Power OFF→ON”
Serial communication timeout happens if the communication cable is broken, cycle exceeds parameter No. 56, or wrong protocol is used. The manual's first action is: “Power OFF→ON”
Parameter error occurs due to servo amplifier faults rewriting parameters, incorrect regenerative brake settings, or EEPROM write limits exceeded. The manual's first action is: “Power OFF→ON”