Precharge Under Voltage

When error [5.7114] occurs, the robot switches to STO (servo off) and stops.

• Servo on fails, usually right after the controller is turned on.
• It often starts after a power outage or an unstable mains supply.
• It is often shown together with 5.7122 (STO relay fault).

[5.7114] Safety controller category

Under-voltage occurred on precharge voltage.
Param 1: CPU Number
Param 2: Min Value
Param 3: Measured value

At servo on, the controller first charges the motor power circuit (precharge). This error means the voltage did not reach the required minimum, so the robot does not turn the motors on.

• Motor power supply in the controller — the 48V power supply is not delivering the right voltage, often after a power outage or surge.
• Mains supply or grounding — an unstable supply, or a poor ground connection shared with other equipment such as a welding machine.
• Wiring of safety signals — safety or I/O signals connected incorrectly.
• A fault in the robot arm — less often, the first joint's electronics.

• Turn the controller off, wait about a minute, and turn it on again.
• Check whether there was a power outage, voltage drop or surge just before the error. Check that the controller's power outlet and cable are in good condition, and that the supply voltage is within the specification.
• If the robot shares power or ground with a welding machine or other large equipment, check the ground connections.
• Check that the robot arm cable is firmly connected at the controller.
• If the safety I/O or digital I/O wiring was recently changed, check it against the installation manual.

If the error returns after a restart, contact your distributor.

• Robot model and serial number
• Software version of the controller
• The error code with its Param values (the measured voltage), all codes shown with it, and the date and time
• Whether there was a power outage, and the supply voltage used
• The controller log exported right after the error

• 5.7122 STO relay fault occurred
• 5.7111 Under-voltage occurred on 48V motor voltage
• 4.1023 Communication Error-Heart Beat