What causes Otis error 99?

Encoder leads for direction (A and A/NOT) are reversed.

How do you fix Otis fault code 99?

1. Reverse the connections for the encoder signals A and A/NOT.

REVERSED TACH FAULT

Otis · DSD 412 DC Elevator Drive

What does 99 mean?

The digital encoder signals and motor voltage signals do not agree in their indicated direction of rotation. This typically points to a reversal in the encoder's directional feedback wiring.

Common Causes

Encoder leads for direction (A and A/NOT) are reversed.

REVERSED TACH FAULT

What does 99 mean?

Common Causes

REVERSED TACH FAULT

What does 99 mean?

Common Causes

Repair Steps & Checklist

Related Faults