How to Read Siemens SINUMERIK Alarm Numbers

Siemens SINUMERIK controls use a different alarm numbering system than Fanuc or Haas. The numbers look like random digits at first. But once you understand the structure, you can decode alarms faster and troubleshoot more efficiently.

This guide explains how Siemens alarm numbers work, what the ranges mean, and how to interpret the most common alarms you will see on 840D, 828D, and other SINUMERIK controls.

The Structure of Siemens Alarm Numbers

Siemens organizes alarms into ranges based on the subsystem that generated them. The first digit tells you the general category. The subsequent digits narrow it down.

Alarm Number Ranges

1xxx alarms: General NC alarms. These cover basic control functions, program errors, and general system faults.

2xxx alarms: Channel-specific alarms. These relate to program execution, tool management, and channel synchronization on multi-channel machines.

3xxx alarms: Axis-specific alarms. Each axis can generate these. They cover servo faults, limit switches, and axis-specific errors.

4xxx alarms: General drive alarms. These come from the SINAMICS drive system and affect all drive components.

5xxx alarms: Channel and program alarms. These relate to part program execution, cycles, and program structure.

6xxx alarms: PLC alarms. These originate from the integrated PLC and cover I/O, safety systems, and machine-specific logic.

7xxx alarms: User alarms. Machine builders use these for custom functions and machine-specific warnings.

8xxx and 9xxx alarms: Reserved for advanced functions and manufacturer-specific uses.

Understanding these ranges helps you immediately narrow down where to look when an alarm hits.

Common 1xxx General Alarms

These alarms affect the entire control system.

Alarm 1000: Emergency Stop Active

The emergency stop circuit is open. Check all E-stop mushrooms, door switches, and safety gates. The control monitors a safety chain. Any break in that chain triggers this alarm.

Trace the E-stop wiring. Look for loose terminals, broken wires in flex conduit, or failed switches. On machines with safety PLCs, use the safety diagnostic screen to see exactly which input opened.

Alarm 1010: Control Battery Alarm

The NC battery voltage is low. Replace the battery during the next maintenance window. Do not wait. If the battery dies completely, you lose all part programs, tool data, and parameters.

The battery maintains memory when power is off. SINUMERIK controls typically use a 3.6V lithium battery. Replacement takes minutes but saves hours of reprogramming.

Alarm 1020: NC Memory Full

The part program memory is full. Delete old programs or archive them to external storage. Siemens controls have generous memory, but shops that never clean up their program directory eventually hit the limit.

Organize programs by customer or date. Archive completed jobs to USB or network storage. Establish a program retention policy.

Alarm 1030: System Error

This is a serious internal fault. Document the alarm number and any sub-codes. Contact Siemens or your machine builder. System errors indicate firmware bugs or hardware failures that require manufacturer support.

Common 2xxx Channel Alarms

These alarms relate to specific channels on the control. Most machines use channel 1 only. Multi-spindle or multi-turret machines use multiple channels.

Alarm 2000: Channel Not Ready

The channel failed to initialize properly. This usually follows another alarm. Check the alarm history to see what triggered it. Channel not ready is often a secondary alarm that clears when you fix the primary fault.

Alarm 2010: Programmed Speed Too High

A program commanded a spindle speed or axis feed that exceeds machine limits. Check the program. Verify the maximum speeds in the machine parameters. The program may come from a different machine with different capabilities.

Alarm 2020: Tool Change Error

The tool changer did not complete its cycle. Siemens controls integrate tightly with machine tool changers. The PLC logic monitors every step. This alarm indicates a timeout or position error.

Check the tool magazine. Verify all positions are clear. Look for mechanical binding, low air pressure, or sensor failures. The tool change cycle depends on dozens of interlocks working correctly.

Common 3xxx Axis Alarms

These are the servo-related alarms you will see most often.

Alarm 3000: Axis Hardware Fault

The drive detected a hardware problem. Check the SINAMICS drive display. Look for fault codes on the motor module. Common causes include overcurrent, ground faults, and encoder errors.

Each axis has a motor module in the drive cabinet. The module displays status and fault codes. Learn to read these codes. They tell you exactly what failed.

Alarm 3010: Axis Overtravel

An axis hit a limit switch. This can be a soft limit programmed in parameters or a hard limit switch at the end of travel. Jog the axis away from the limit. Check why it hit the limit. A lost position reference or program error usually causes this.

If the axis will not move because it is on the limit, use the manufacturer procedure to override. This typically requires a special key switch or password.

Alarm 3020: Following Error Too Large

The servo could not keep up with the commanded position. This is similar to Fanuc SV0410. Check for mechanical binding, excessive load, or servo tuning issues.

Monitor the following error in the service display. Normal operation shows small errors that the servo corrects. Large errors indicate problems.

Alarm 3030: Encoder Fault

The position feedback signal has problems. Check encoder cables for damage. Look for oil contamination in connectors. Verify the encoder power supply voltage.

Siemens systems use serial encoders with high-speed data links. Cable quality matters. Use only specified cables. Do not splice or extend encoder cables.

Common 4xxx Drive Alarms

These come from the SINAMICS drive system.

Alarm 4000: Drive Bus Fault

Communication between the NC and drives failed. Check the DRIVE-CLiQ cables. These are special Siemens cables that connect the control to drive components. They are not Ethernet cables despite looking similar.

Look for loose connections, damaged cables, or electromagnetic interference. Drive bus faults often appear after maintenance when cables get disturbed.

Alarm 4010: Infeed Fault

The power supply module detected an error. Check incoming power voltage and phase rotation. Verify the line reactor connections. Infeed faults often indicate power quality issues.

Alarm 4020: Motor Module Fault

A specific motor module failed. The display shows which module. Check the module status LEDs. Look up the fault code in the SINAMICS documentation.

Common 6xxx PLC Alarms

These originate from the PLC program and cover machine-specific functions.

Alarm 6000: General PLC Alarm

This is a catch-all for PLC-detected faults. The alarm text usually describes the specific problem. PLC alarms are programmed by the machine builder, so they vary between manufacturers.

Alarm 6100: Lubrication Fault

The automatic lubrication system failed. Check the lube pump, level switches, and distribution lines. Way lube failures cause rapid machine wear. Fix these immediately.

Alarm 6200: Coolant Fault

The coolant system has a problem. Check pump status, level, and pressure. Verify the coolant concentration. Dirty or depleted coolant causes tool life and surface finish problems.

Alarm 6500: Door Interlock

A safety door is open or the interlock switch failed. Check all guard doors and access panels. Safety systems on Siemens machines are sophisticated. Do not bypass them. Find and fix the root cause.

Reading Alarm Texts and Help

SINUMERIK controls provide detailed alarm text and often online help. Use this feature.

Press the help key when an alarm is active. The control displays additional information about the alarm cause and recommended remedies. This is valuable for uncommon alarms.

Check the alarm log. Siemens controls maintain extensive alarm history. This shows when alarms occurred, how long they lasted, and what cleared them. Use this data to identify intermittent problems.

Using the Service Displays

Siemens provides service displays for deep diagnostics.

Axis service display: Shows real-time position, following error, servo load, and encoder status. Use this to diagnose servo problems.

Drive service display: Shows SINAMICS parameters, status words, and fault buffers. Essential for drive troubleshooting.

PLC status: Shows input and output states, flag bits, and data blocks. Use this to trace PLC logic problems.

Learn to navigate these displays. They provide information that speeds up troubleshooting significantly.

Documentation You Need

Keep these documents accessible:

Machine parameter list. Every machine has unique parameters. Know where the backup is stored.

SINAMICS drive manual. Fault codes and parameters are documented here.

PLC program documentation. If available, this explains what the PLC logic does and what each alarm means.

Electrical schematics. Essential for tracing wiring problems.

When to Call for Support

Some Siemens alarms need manufacturer support. System errors, firmware faults, and complex drive problems require specialized knowledge and tools.

If you see repeated alarms that clear with power cycling, you have an intermittent hardware fault developing. Get ahead of it before it becomes a hard failure.

Understanding Siemens alarm structure makes you faster at troubleshooting. You spend less time guessing and more time fixing the real problem.