Danfoss FC 300 Design Manual page 49

FC 300 Design Guide
3.10 Smart Logic Controller - AutomationDrive FC 300
The Smart Logic Control (SLC) is essentially a sequence of user defined actions (see par. 13-52
event
associated user defined (see par. 13-51
Events actions
and are each numbered and are linked in pairs called states. This means that when
[1]
is executed. After this, the conditions of
are placed in array parameters.
event
Only one will be evaluated at any time. If an
events
other will be evaluated. This means that when the SLC starts, it evaluates
[1] is evaluated TRUE, the SLC executes
It is possible to program from 0 to 20
event / action
has been executed, the sequence starts over again from
event [1] / action [1] . The illustration shows an example with three
events / actions :
3.11 Extreme Running Conditions
Short Circuit (Motor Phase – Phase)
The frequency converter is protected against short circuits by means of current measurement in each of the three motor phases or in the DC link. A short
circuit between two output phases will cause an overcurrent in the inverter. The inverter will be turned off individually when the short circuit current
exceeds the permitted value (Alarm 16 Trip Lock).
To protect the frequency converter against a short circuit at the load sharing and brake outputs please see the design guidelines.
Switching on the Output
Switching on the output between the motor and the frequency converter is fully permitted. You cannot damage the frequency converter in any way by
switching on the output. However, fault messages may appear.
Motor-generated Over-voltage
The voltage in the intermediate circuit is increased when the motor acts as a generator. This occurs in following cases:
1. The load drives the motor (at constant output frequency from the frequency converter), ie. the load generates energy.
2. During deceleration ("ramp-down") if the moment of inertia is high, the friction is low and the ramp-down time is too short for the energy to be
dissipated as a loss in the frequency converter, the motor and the installation.
3. Incorrect slip compensation setting may cause higher DC link voltage.
The control unit may attempt to correct the ramp if possible (par. 2-17
The inverter turns off to protect the transistors and the intermediate circuit capacitors when a certain voltage level is reached.
See par. 2-10 Brake Function and par. 2-17
SL Controller Event
) is evaluated as TRUE by the SLC.
event [2]
will be evaluated and if evaluated TRUE,
event
is evaluated as FALSE, nothing happens (in the SLC) during the present scan interval and no
action [1] and starts evaluating event [2]
events actions
and . When the last
Over-voltage Control
Over-voltage Control to select the method used for controlling the intermediate circuit voltage level.
MG.33.BC.02 - VLT ® is a registered Danfoss trademark
3 Introduction to AutomationDrive FC 300
SL Controller Action ) executed by the SLC when the
event [1]
is fulfilled (attains the value TRUE),
action [2]
will be executed and so on. Events and actions
event [1] event [1]
(and only ) each scan interval. Only when
.
.
action
3
event
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