BECKHOFF AX2000 CANopen communication profile - Manual (Page 119)

6.1.4 Example of Homing
When the AX2000/2500 is operated as a linear axis, a reference/homing point must be defined
before positioning tasks can be executed. This can be done simply through Set reference point
(control word Bit 12 = 0 -> 1 -> 0 or homing type 35 in Homing mode) or by starting a homing move-
ment, either in the manufacturer-specific mode Homing/reference (0xF9) or in the Homing mode
(0x6).
This example shows the procedure in the Homing mode.
First switch over to the Homing movement mode:
COB-ID Control byte Index Sub-
index
Data Comment
Low byte High byte
601 2F 60 60 00 h F9 00 00 00 Homing mode
581 60 60 60 00 h 00 00 00 00 O.K. signal
In the following example, all parameters that affect the homing movement are set via the bus. If you
can be absolutely certain that no-one has altered the parameters in the amplifier, then this part can
be omitted, since the amplifiers save the data in non-volatile memory. (The inputs must have been
previously configured as limit switches.)
COB-ID Control byte Index Sub-
index
Data Comment
Low byte High byte
601 2F 24 20 01 h 17 00 00 00
homing to limit switch & re-
solver zero mark
581 60 24 20 01 h 00 00 00 00 OK
601 2F 24 20 02 h 00 00 00 00 negative direction
581 60 24 20 02 h 00 00 00 00 OK
601 2B 24 20 03 h 10 27 00 00 v = 10mm/s
581 60 24 20 03 h 00 00 00 00 OK
601 2B 24 20 04 h 32 00 00 00 accel. ramp 50ms
581 60 24 20 04 h 00 00 00 00 OK
601 2B 24 20 05 h 32 00 00 00 decel. ramp 50ms
581 60 24 20 05 h 00 00 00 00 OK
601 23 24 20 06 h 30 75 00 00 reference offset 30000μm
581 60 24 20 06 h 00 00 00 00 OK
To check the bit signals that are important for the homing movement, the PDO for enhanced status
(PDO 23) must be used. PDO 23 is selected as TPDO 1:
COB-ID Control byte Index Sub-
index
Data Comment
Low byte High byte
601 2F 00 2A 00 h 17 00 00 00 select PDO 23 as 1 st TPDO
601 60 00 2A 00 h 00 00 00 00 response telegram
TPDO1 is thus composed of 6 bytes, whereby the first two bytes contain the CANopen status word
(Object 6041), and the other four bytes contain the manufacturer-specific status register (Object
1002).
This assignment can be queried through the Objects for the PDO mapping (Object 1A00
h
,
Sub-index 00
h
-02
h
). The PDOs are subsequently enabled through an NMT Object:
COB-ID Command specifier (CS) Node-ID
0 1 1
From now on, status changes for TPDO1 will be automatically reported.
CANopen for AX2000/2500 119
BECKHOFF
07/2007
Appendix