User Manual

CANopen Manual for TMCM-1140, TMCM-1160, and TMCM-1180 (Rev. 2.01 / 2017-JUL-26) 38
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4.3 Homing Mode
This clause describes the method by which a drive seeks the home position (reference point). There are
various methods of achieving this using limit switches at the ends of travel or a home switch in mid-
travel. Some methods also use the index (zero) pulse train from an incremental encoder. The user may
specify the speeds, acceleration and the method of homing.
There is no output data except for those bits in the statusword, which return the status or result of the
homing process and the demand to the position control loops.
There are four sources of the homing signal available: these are positive and negative limit switches, the
home switch and the index pulse from an encoder.
Figure 4.2 shows the defined input objects as well as the output objects. The user can specify the speeds,
acceleration and method of homing. The home offset object 607C
h
allows displacing zero in the coordinate
system for the home position.
Homing
method
Controlword 6040
h
Homing method 6098
h
Homing speeds 6099
h
Homing acceleration 609A
h
Home offset 607C
h
Statusword 6041
h
Position demand internal value 60FC
h
or
Position demand value 6062
h
Figure 4.2 Homing mode function
BY CHOOSING A HOMING METHOD, THE FOLLOWING IS DETERMINED:
- the homing signal (positive limit switch, negative limit switch, and home switch),
- the direction of actuation and where appropriate, and
- the position of the index pulse.
The home position and the zero position are offset by the home offset (see object 607C
h
).
THERE ARE FOUR SOURCES OF HOMING SIGNAL AVAILABLE:
- negative and positive homing switches
- home switch
- index pulse of an encoder
For the operation of positioning drives, an exact knowledge of the absolute position is normally required.
Since for cost reasons drives often do not have an absolute encoder, a homing operation is necessary.
There are several application specific methods. The homing method is used for selection.
Please refer to object 6060
h
(section 4.1.6) for information about how to choose an operation mode.
Object 6061
h
(section 4.1.7) shows the operation mode that is set.