SRVO-071: SPHAL alarm (feedback speed excess)
The encoder reported a speed physically implausible for the axis - excessive feedback speed.
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.
- Loose or faulty encoder cable connection.
- Electrical noise on a poorly shielded feedback line.
- High-speed collision event on certain models.
- Aux-axis torque-limit logic: resetting torque limit to 100% while the axis is moving fast.
- Encoder, amplifier, or cabling failure.
How to fix it
- Reseat the encoder cable connectors; verify shield grounding.
- If it fired at a collision event, inspect the robot before resetting and resuming.
- On aux axes using Torque Limit, restructure the program so position error is near zero before the limit resets to 100%.
- Then hardware in order: motor (re-master after), amplifier, connection cable, internal encoder cable. Power-cycle to clear.