bb Base Block (Status) fault in delta drive

bb Base Block (Status) fault in delta drive troubleshooting

Description

bb is technically a status, not a hard fault, but it often confuses operators. It stands for "Base Block," meaning the drive output is electronically blocked (IGBTs are off) and the motor is coasting. It appears when an external signal forces the drive to stop output immediately.

Causes

1. External Signal: An input terminal programmed for "External Base Block" (N.O. or N.C.) has been activated.
2. Speed Search: During "Catch on Fly," the drive displays bb while sensing motor speed.
3. Interlock: Used often in elevator or crane applications to ensure the mechanical brake is engaged before the drive releases torque.

Solution

If bb is unexpected:
1. Check Digital Inputs: Identify which terminal is assigned to Base Block (B.B.) in the parameters and check its status.
2. Check Wiring: A loose wire on a Normally Closed safety circuit wired to B.B. will trigger this.
3. Disable: If the function is not needed, set the corresponding digital input parameter to "No Function" or "0".