405
SAFETY CIRCUIT FAULT
Otis · DSD 412 Elevator System
What does 405 mean?
The DSD 412 drive detects that the Safety Circuit, connected between terminals TB3-1 and TB3-6 on the power supply, unexpectedly opened while the drive was in run mode. The safety chain must be closed for at least 100ms before enabling the drive. This fault is disabled if the speed is below the low speed threshold defined by parameter #64.
Common Causes
- Intermittent connections within the Safety Chain.
Repair Steps & Checklist
Click steps to track your progress.
- 1
Check for intermittent connections in the Safety Chain wiring between terminals TB3-1 and TB3-6 on the power supply.
Verified technical data. Last updated: March 2026
Related Faults
Source: Otis DSD 412 Elevator System