3 different servo homing methods

[unsaint32]

Can you help me understand the differences between the following three different homing methods? Examples would be very helpful for a novice like me. I'm referring to servo setup using Kinetix6500 & Rslogix 5K. The underlined part is from AB literatures. Following are my questions.

1) Active homing mode with immediate sequence: This sequence sets the axis position to the Home Position without moving the axis.
The current axis position becomes the home position then?

2) Passive homing mode with immediate sequence: The controller immediately assigns the Home Position to the current axis actual position.
Isn't it exactly the same as Active/immediate homing?

3) Absolute homing mode with immediate sequence: It establishes the true absolute position of the axis by applying the configured Home Position to the reported position of the absolute feedback device.
So, the current position becomes the offset to the designated absolute home position?

 

[rootboy]

Kind of a strange question...

Basically I have two things that I do with it. Set it, and move to it. I like to keep things simple, like me.

Peter N. might have some more insight about this. He's the "motion man" around these parts.

 

[kamenges]

Generally speaking, Logix homing sequences require the drive for the axis you are homing to at least be enabled. This is where the distinction between the first two variants comes in. Active homing requires the axis to be active (enabled and under control) while passive homing does not. You can perform passive homing on a disables or virtual axis. In either case an offset is defined based on the difference between the internal axis feedback position and the reported position. This offset is used until another homing is performed or until the physical feedback position can no longer be trusted (drive power is lost).

Absolute homing can only be performed an an axis that supports absolute position feedback. I think absolute homing will write to the feedback device internal offset position. This means the offset is stored in the feedback device itself. So you would be able to remove a motor from one drive, connect it to another drive and the feedback position would remain unchanged. The new drive would likely still force you to perform a reference but the initial position from the feedback device would not have changed.

Keith