Device control
State diagram
Overview
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KHB 13.0003-EN
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8
Device control
8.1
State diagram
8.1.1
Overview
The following chapter describes how the drive controller is controlled under CANopen, i.e.
how, for instance, the power stage is switched on or how an error is acknowledged.
Stop!
Uncontrolled rotation of the motor
An incorrectly parameterised drive controller can cause uncontrolled rotation
of the motor.
Possible consequences:
ƒ
This may result in property damage.
Protective measures:
ƒ
Before the initital switch-on of the power stage, ensure that the drive
controller is really parameterised with the correct parameters.
Under CANopen, the entire control of the drive controller is implemented using two
objects: The master can control the drive controller via the
control word
, and the state of
the drive controller can be read back via the
status word
object. To explain the control of
the drive controller, the following terms are used:
ƒ
State
Depending on the power stage being switched on or an error having occurred, the drive
controller is in different states. The states defined under CANopen are described in this
chapter.
Example: Switch_On_Disabled
ƒ
State transition
CANopennot only defines the states, but also how toget fromone stateto another(e.g.
for acknowledging an error). State transitions are initiated by the master by setting bits
in the
control word
or internally by the drive controller if, for instance, the controller
detects an error.
ƒ
Command
To initiate state transitions, certain bit combinations must be set in the
control word
.
Such a combination is called a command.
Example: Enable operation
ƒ
State diagram (state machine)
All states and state transitions together form the state diagram, i.e. the overview of all
states and the possible transitions.
