Operating modes
Positioning
Functional description
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114
KHB 13.0003-EN 2.0
9.4.3
Functional description
There are two ways to transfer a target position to the drive controller:
ƒ
Simple travel task
When the drive controller has reached a target position, it signals this to the master with
the
target_reached
bit (bit 10 in the
status word
object). In this operating mode, the drive
controller stops when it has reached the target.
ƒ
Sequence of travel tasks
After the drive controller has reached a target, it immediately starts to approach the next
target.
Interruption of a running task by a new travel task
The running positioning task is interrupted immediately and the new travel task is started.
These three methods are controlled by the
new_set_point
and
change_set_immediately
bits in the
control word
object and by the
set_point_acknowledge
bit in the
status word
object. The relationship between these bits is an interrogation/ response relationship. This
makes it possible to prepare a new travel task while the old one is still running.
(1)
1
1
1
(2)
(3)
(4)
(5)
(6)
(7)
t
t
t
data_
valid
new_
set_
point
set_
point_
acknowledge
931e_406
Fig. 15
Transfer of a travel task between master and drive controller
First the positioning data (target position, travelling speed and acceleration) are
transferred to the drive controller. When the positioning data record is written completely
(1), the master can start the positioning by setting the
new_set_point
bit in the
control
word
to ”1” (2).
After the drive controller has recognised the new data and transferred this data into its
buffer, the controller signals this to the master by setting the
set_point_acknowledge
bit
in the
status word
(3).
Then the master can start to write a new positioning data record to the drive controller (4)
and delete the
new_set_point
bit again (5). The drive controller signals that it is ready to
accept a new travel task (6) by setting the
set_point_acknowledge
bit to ”0”. Prior to this,
the master may not start a new positioning (7).