Don't understand +Fa,-Fa per ANSI B92.1

[[ma...]]

We have recently version gearpro.

Pre version(gearpro) has fha(helix error).

I don't understand why the ANSI B92.1 specification released before 2000 has been changed to after 2025.

This is a sudden development. Fa represents the total profile error and is an absolute value. Fa, which has a vector value, does not align with higher-level theories. In other measuring instruments, the Fa value is an absolute value. The Zeiss Gear Pro is the only exception. We managed it using fha (helix error). This is because fha (helix error) is the only parameter that possesses directionality.