Troubleshooting Mori Seiki EX Alarms: A Field Guide If you're staring at a Mori Seiki EX Alarm, you’re dealing with an "External" or PLC-side error. Unlike standard Fanuc CNC alarms that focus on the internal motion control, EX alarms are usually triggered by peripheral machine conditions—like a door that won't lock, a pressure sensor that's tripped, or a turret that isn't seated properly.
Below is a breakdown of common Mori Seiki EX alarm codes and practical steps to clear them. Common Mori Seiki EX Alarm Codes Message / Description Primary Fix / Check EX0069 Door Lock Time Over Check for chips in the door track or a faulty lock sensor. EX0099 Panel Alarm
Typically related to the operator panel or power supply conditions. EX0453 Mill Spindle Alarm A fault is present in the spindle amplifier or drive unit. EX0551 Electrical Cabinet Overheat
Clean the cabinet filters and check if the cooling fans are spinning. EX0557 Oil-Air Lubricant Pressure Low
Verify your lubricant levels and check for leaks in the air lines. EX2027 Interlock Key Switch Release
The interlock was turned during an automatic cycle or feed hold. EX2566 High-Pressure Coolant System General abnormality in the coolant pump or system pressure. EX2595 Coolant Unit Filter Clogged The filter is restricted; it needs cleaning or replacement. EX2909 Door is Opening (Timer Power-on)
Front door was not closed when the weekly timer turned the machine on. Pro Troubleshooting Steps
Check Physical Interlocks: Many EX alarms are "safety chain" issues. Ensure all doors are fully closed, the interlock key is in the correct position, and emergency stop buttons are released.
Inspect Consumables: Alarms like EX0557 (Lubricant) or EX2595 (Filter) are often simple maintenance reminders. Before calling a tech, verify oil levels and clean your filters. mori seiki ex alarm list
Ladder Logic Diagnosis: If the alarm message is vague, seasoned operators use the NC Ladder screen to find the specific bit (e.g., an X-input or R-bit) triggering the alarm. This tells you exactly which sensor or switch the machine is waiting for.
Power Cycle & Re-Homing: For transient errors, especially after a battery change (see EX2562), you may need to reset the home position via parameters (often Parameter 1815 for Fanuc-based Mori machines). Why "EX" Alarms Matter
Because these are machine-specific rather than control-specific, they vary between a Mori Seiki NLX lathe and an NHX machining center. Always refer to your machine’s specific Maintenance Manual for the definitive EX list tailored to your serial number.
Do you have a specific code currently on your screen that isn't listed here? Mori Seiki SL 15 with MF-T6 controller: resolving APC alarm
On Mori Seiki machines (typically using MAPPS interfaces or Fanuc controls), EX alarms refer to External (PLC) Alarms. These are generated by the machine tool builder rather than the CNC control itself, usually relating to peripheral hardware like the chip conveyor, tool changer, or coolant system. Common Mori Seiki EX Alarm Categories
Because EX alarms are defined by the machine builder (Mori Seiki), the exact code can vary slightly between models (e.g., NLX, NTX, DuraVertical). However, they generally follow these ranges:
EX0001 – EX0499: Safety and Operation Alarms (e.g., Door Open, Emergency Stop).
EX0500 – EX0999: Lubrication and Hydraulic Alarms (e.g., Low Oil Level, Pressure Drop). EX1000 – EX1999: Tool Changer (ATC) and Turret Alarms. Troubleshooting Mori Seiki EX Alarms: A Field Guide
EX2000 – EX2999: Peripheral Equipment (e.g., Chip Conveyor, Bar Feeder, High-Pressure Coolant). Frequently Encountered EX Alarms Alarm Code Common Solution EX0000 Emergency Stop
Check all E-stop buttons (including bar feeder or conveyor). EX0501 Lubrication Level Low
Refill the way lube tank. Check for leaks if it empties quickly. EX1024 Turret Index Error
The turret failed to seat or clamp. Check for chips in the turret face. EX2041 Chip Conveyor Overload
Usually caused by a "rat's nest" of chips jamming the belt. Reverse the belt to clear. EX2500 Door Interlock
The door was opened during a cycle or the lock sensor is dirty/misaligned. How to Troubleshoot EX Alarms
Check the Message: On the MAPPS or Fanuc screen, press the [MESSAGE] or [ALARM] hard key. EX alarms usually provide a text string (e.g., EX0501 LUBRICATION PRESSURE LOW).
Check the Ladder/Diagnostics: If the message is vague, look at the Diagnostic (DGNOS) bits. Mori Seiki manuals often list specific bits that trigger these alarms. Stop machine motion; ensure safe state
Inspect Physical Sensors: Since EX alarms are PLC-based, they are often triggered by a limit switch, proximity sensor, or pressure switch.
Consult the Manual: Every Mori Seiki machine is shipped with a "Maintenance Manual" or "Ladder Diagram" specific to its serial number. You can find digital versions or parts lists through Scribd or the DMG MORI Service Portal.
Do you have a specific EX alarm number appearing on your screen right now?
Sometimes the display only shows: EX1051 ... No PLC message configured. In this case, you need to read the PMC diagnostic bits.
If EX1011 LUBRICATION PRESSURE LOW happens every Monday morning, the lube pump may be losing prime over weekends. Install a check valve or run a lubrication cycle (M70) on startup.
R1000.1 in the PMC.R1000.1 = 1, the alarm is active. Go to the PLC ladder and search for R1000.1 to see what physical input (X address) triggers it.Common X addresses for Mori Seiki lathes:
X4.2 – Chuck clamp proximityX2.7 – Hydraulic low level switchX12.5 – Tool post home positionKnowing this bypasses the need for a full EX list in an emergency.
No system is perfect, and the Mori Seiki EX list has its quirks:
The Mori Seiki EX series (including EX-101, EX-106, etc.) is known for reliability, but like all CNC machines, it communicates issues through specific alarm codes. Understanding the difference between System Alarms and Machine Alarms is the first step in troubleshooting.