SRVO-071: SPHAL alarm (feedback speed excess)

What it means

The encoder reported a speed physically implausible for the axis - excessive feedback speed. Real overspeed is rare; noise, a loose feedback connector, or (on some models) a high-speed collision are the usual explanations, with a specific torque-limit gotcha on auxiliary axes.

Common causes

Ranked by what technicians most often find, most likely first.

1. Loose or faulty encoder cable connection.
2. Electrical noise on a poorly shielded feedback line.
3. High-speed collision event on certain models.
4. Aux-axis torque-limit logic: resetting torque limit to 100% while the axis is moving fast.
5. Encoder, amplifier, or cabling failure.

How to fix it

1. Reseat the encoder cable connectors; verify shield grounding.
2. If it fired at a collision event, inspect the robot before resetting and resuming.
3. On aux axes using Torque Limit, restructure the program so position error is near zero before the limit resets to 100%.
4. Then hardware in order: motor (re-master after), amplifier, connection cable, internal encoder cable. Power-cycle to clear.

Related codes

• SRVO-070STBERR alarm (pulse coder framing error)
• SRVO-072PMAL alarm (pulse coder fault)
• SRVO-069CRCERR alarm (pulse coder data corrupt)
• SRVO-073CMAL alarm (pulse coder noise/fault)
• SRVO-068DTERR alarm (pulse coder no response)
• SRVO-074LDAL alarm (pulse coder LED broken)
• SRVO-067OHAL2 alarm (pulse coder overheat)
• SRVO-066CSAL alarm (pulse coder checksum)