Mitsubishi Mr-j2-200ct Alarm List !!hot!!

The is a classic, robust servo amplifier from the renowned J2 Series, widely used in CNC machinery, industrial robots, and factory automation systems. Despite its reliability, like all precision electronics, it is susceptible to faults. When an alarm triggers, the servo amplifier stops the motor and displays an error code on its 3-digit, 7-segment LED display.

Short circuit in U/V/W phases; power module fault; high load Repair output wiring; check motor for mechanical jams Overvoltage Regenerative energy exceeds capacity; input voltage > 400V Check regenerative resistor wiring; verify input voltage Parameter Error mitsubishi mr-j2-200ct alarm list

Indicates a RAM or memory fault within the amplifier. Replacing the servo amplifier is usually required. The is a classic, robust servo amplifier from

| Alarm Code | Alarm Name | Description & Cause | Corrective Action | | :--- | :--- | :--- | :--- | | | Encoder Communication Error | Data transfer disturbed between encoder and amplifier. Loose connector, noise, or broken cable. | Reseat encoder connector (CN2). Check shield continuity. Replace encoder cable (max 20m). Use ferrite core. | | AL.24 | Encoder Initial Position Error | Motor’s absolute encoder fails to send initial pole position data. Battery voltage low (for absolute system) or encoder damaged. | Replace encoder battery (if absolute). If incremental, reset multi-turn limit. Re-boot with motor at standstill. | | AL.25 | Absolute Encoder Overvoltage | Internal voltage to encoder memory exceeds 3.3V. | Replace encoder battery. Clear alarm via parameter (Pa25 = 1). Then recalibrate home position. | | AL.30 | Regenerative Overload (Continuous) | Regenerative resistor exceeded thermal capacity continuously for >30 seconds. | Stop frequent start/stop cycles. Install larger external regenerative resistor. Add cooling fan. | | AL.31 | Motor Overheat | Thermal protector inside motor activated (due to ambient >40°C or continuous overload). | Reduce load. Check motor fan. Measure motor surface temp (<130°C for insulation class B). | | AL.32 | Overcurrent at Power ON | Short circuit detected immediately when main power applied. Severe phase-to-phase short in motor or wiring. | Do not re-power repeatedly. Disconnect motor leads. If alarm clears, motor/wiring fault. If persists, amplifier dead. | | AL.33 | Overvoltage at Power ON | Bus voltage too high before operation. Input voltage >264V AC. | Measure incoming voltage. Use line reactor or voltage stabilizer. | Short circuit in U/V/W phases; power module fault;