A consolidated reference for the Yaskawa Sigma-7 alarm codes you are most likely to see on the SERVOPACK and in SigmaWin+, with the common remote-checkable cause for each and the parameter to verify before you consider a replacement.
The Sigma-7 SERVOPACK shows an alarm code on its 7-segment display (A.xx or F.xx format) and logs it in the alarm history accessible in SigmaWin+ or the panel monitor. Pairing the code with the motor current, encoder feedback and the recent-change log is how a remote specialist separates a cable/parameter issue from a genuine SERVOPACK fault.
| Alarm source | Where you see it | What it tells you |
|---|---|---|
| Displayed code | SERVOPACK 7-segment display | The A.xx / F.xx code that classes the alarm |
| Alarm history | SigmaWin+ / panel monitor | Recent alarms in sequence with occurrence counts |
| Live values | SigmaWin+ monitor | Motor current, encoder position, speed at the moment |
The table lists the most common Sigma-7 codes, their meaning, and the first remote check. Likelihood reflects field frequency.
| Code | Meaning | Likelihood | First Remote Check |
|---|---|---|---|
| A.04 | Encoder data error — encoder feedback circuit issue | Med–High | Check the encoder cable, connector and encoder power via SigmaWin+ diagnostics |
| A.10 / A.11 | Encoder battery or memory alarm | Med | Confirm the absolute encoder battery state and replace if low; re-home the axis |
| F.10 | Main circuit overcurrent — output current above rating | Med–High | Note the current trend; check the motor cable, load and amplifier tuning |
| F.51 / F.52 | Motor overload — thermal protection tripped | Med | Check motor current vs nameplate and the duty cycle; look for mechanical binding |
| A.30 | Position deviation too large | Med | Review the following-error limit and the load; confirm the motion profile is achievable |
| F.30 | Encoder communications noise or disconnection | Low–Med | Check the encoder cable routing, shielding and connectors |
Many Sigma-7 alarms share a root cause family. Reading the motor current, encoder feedback and the alarm history sequence together is what identifies the actual trigger.
Work through these in order. Each step is something you can perform and report back on without opening the SERVOPACK or removing parts.
Note the displayed A/F code and the alarm history sequence. The code's position tells you which alarm started it.
Note motor current, encoder position and speed around the alarm. Overcurrent vs encoder fault vs deviation is told apart by these numbers, not the code alone.
Was there a wiring edit, a cable reroute, a new load, or a parameter change right before? Recent changes usually reveal the trigger.
Confirm the amplifier is correctly sized and tuned for the motor and load. Wrong tuning or sizing is a common cause of overcurrent and deviation alarms.
After aligning parameters and confirming the cable path, clear the alarm and verify the axis holds without a repeated trip for a sustained motion cycle.
A Sigma-7 alarm is a current, encoder or deviation path more often than a SERVOPACK failure. Cross-reference the specific conditions: Servo overcurrent · Following error · All motor/drive symptoms · Servo technology.
In remote practice, most Sigma-7 alarms are current, encoder or deviation paths and are resolved from the alarm history, the SERVOPACK state and the tuning/load review — not by replacing the SERVOPACK. Escalate to a specialist when an A-series alarm needs the full motor/encoder data, when an alarm survives a power cycle and an encoder reseat, or when production is down and a wrong repair order is the larger cost.
To get the fastest accurate read, send these three things. Everything is read from the SERVOPACK and the tuning tool — no disassembly.
Send these and we can usually confirm whether the fault is remote-resolvable before you book any hands-on visit. pumps, motors and drives troubleshooting guidance
A.04 is an encoder-related alarm — a data error or misconnection on the encoder circuit. It is often a cable, connector, or encoder-power issue that is remotely diagnosable from the alarm history and encoder feedback checks.
F.10 is main-circuit overcurrent and F.51 is motor overload. Both point to a current/load problem or wrong SERVOPACK sizing, and are remotely-checkable from motor current, load and tuning parameters.
Yes. Share the alarm code, SigmaWin+ history and parameter values; a specialist interprets the code and guides recovery. We never take control of your servo system.
Alarm A.04 is an overcurrent-class alarm; appearing only after a period of running suggests rising current demand as the machine warms — a mechanical tightening, a brake not releasing, or thermal drift in the wiring. The alarm history and current trace tell whether it is load, wiring or a genuine SERVOPACK condition.
Send us the error code, a photo of the screen and what you already tried — an independent specialist reviews your case and replies with an evaluation, typically within 24 hours.
Submit Your CaseSend the alarm code, alarm history and live values. We interpret it and guide recovery remotely — no SERVOPACK replacement unless it is genuinely required.
Submit Your Case Connect With SpecialistsWe do not perform hardware repair, we do not replace parts, and we cannot promise a 100% resolution. Our role is limited to remote diagnostic and step-by-step guidance based on the information, photos and logs you share.
Before changing drive parameters or replacing parts, verify against the official documentation from Yaskawa:
Tip: for simple issues, a general-purpose AI assistant can help you interpret a fault code — but always cross-check any corrective action against the official manual before applying it.
The most common amplifier trip path in detail.
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Part of the full library: fault codes by brand — ACS580, S7-1200, ATV320, Sigma-7, CompactLogix, FX5U, VF-2, Robodrill and CFW800.