CANopen Programmer's Manual - Maccon.de

6: Homing Mode Operation CANopen Programmer’s Manual
Homing Overview
Homing is the method by which a drive seeks the home position (also called the datum, reference
point, or zero point). There are various methods of achieving this using:
limit switches at the ends of travel, or
a dedicated home switch.
Most of the methods also use the index pulse input from an incremental encoder.
The amplifier performs homing operations in Homing Mode (Mode Of Operation [index 0x6060, p.
64] =6).
The Homing Function
The homing function provides a set of trajectory parameters to the position loop, as shown below.
The parameters are generated by the homing function and are not directly accessible through
CANopen dictionary objects. They include the profile mode and velocity, acceleration, and
deceleration data.
Home Offset
Homing Method
Homing Speeds
Home Velocity Fast / Slow
Homing Acceleration
Homing
Function
Trajectory
Parameters
Trajectory
Generator
Position Demand
Position
Loop
Initiating and Verifying a Homing Sequence
A homing move is started by setting bit 4 of the Control Word object (index 0x6040, p. 58). The
results of a homing operation can be accessed in the Status Word (index 0x6041, p. 58).
Home Offset
The home offset is the difference between the zero position for the application and the machine
home position (found during homing). During homing the home position is found and once the
homing is completed the zero position is offset from the home position by adding the Home Offset
to the home position. All subsequent absolute moves shall be taken relative to this new zero
position. This is illustrated in the following diagram.
Homing Speeds
There are two homing speeds: fast and slow. The fast speed is used to find the home switch and
the slow speed is used to find the index pulse. (See the Homing Speeds object [index 0x6099, p.
185])
Homing Acceleration
Homing Acceleration (index 0x609A, p. 185) establishes the acceleration to be used for all
accelerations and decelerations with the standard homing modes.
Note that in homing, it is not possible to program a separate deceleration rate.
166 Copley Controls