Emerson FM-3 - Manual (Page 26)

12
FM-3 Programming Module Reference Manual
Figure 10: Sensor and Marker Home Reference Position Example 2
The Home Sensor must be “On” for at least 800
µsec to guarantee that it will be recognized.
Figure 11: Sensor and Marker Home Reference Position Example 3
Home Offset
The Home Offset is the distance from the Reference Position to the final stopping point at the
end of the homing sequence. Regardless of the value you enter for the Offset or which Home
Reference you choose, there is always an offset inherent in the homing process.
The user may either specify a desired offset or allow the drive to calculate an offset
automatically. The drive calculates an offset that guarantees that the motor will not have to
backup to get to the offset position. This is very convenient for unidirectional applications.
The calculated offset is the distance travelled during deceleration ramp from the home
velocity to a stop plus the distance travelled at the home velocity for 800
µsec. This extra
distance is used to guarantee that the motor will not need to backup after the deceleration
ramp.
Marker
Sensor
800 µsec
Direction of Travel
800 µsec
Sensor
Sensor Min.
On Time