These bits activate when the corresponding Hardware Limit is activated. The Hardware Limits are active and enabled by default for safety purposes. When these bits are active, motion is inhibited from continuing in that direction (i.e. when the positive limit is hit, motion cannot proceed in the positive direction, only in the negative). TLIM, which shows the Hardware Limit status, does not have to agree with the TASF bit. TLIM shows the status where TASF bits 15 and 16 are latched to keep motion from occuring any further in that direction.
For instance, moving quickly in the negative direction with a long deceleration ramp will cause the axis to stop once it hits the limit, but it will be past the limit by the time it stops. Therefore, TLIM will show the limit to be inactive, but TASF bit 16 will be active.
1) Connect Hardware Limit switches as stated in the Hardware Reference Guide. They can also be jumpered to Ground with the default hardware configuration.
2) Disable the Hardware Limit inputs with the LH command.