Smart Logic Control - Danfoss FC 300 Design Manual

3. Introduction to FC 300
To reduce the electrical noise from the wires between the brake resistor and the adjustable fre-
quency drive, the wires must be twisted.
For enhanced EMC performance, a metal shield can be used.

3.9.1. Smart Logic Control

3
The smart logic control (SLC) is essentially a sequence of user-defined actions (see par. 13-52)
executed by the SLC when the associated user-defined
TRUE by the SLC.
Events
event [1]
event [2]
and actions are placed in array parameters.
Only one
(in the SLC) during the present scan interval and no other
that when the SLC starts, it evaluates
event [1]
It is possible to program from 0 to 20
actions
and
been executed, the sequence starts over
again from
tion shows an example with three
actions
Short Circuit (Motor Phase – Phase)
The adjustable frequency drive is protected against short circuits by means of current measure-
ment 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 drive 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 adjustable frequency drive is fully permitted.
You cannot damage the adjustable frequency drive in any way by switching on the output. How-
ever, fault messages may appear.
Motor-generated Overvoltage
The voltage in the intermediate circuit is increased when the motor acts as a generator. This occurs
in the following cases:
52
actions
and are each numbered and are linked in pairs called states. This means that when
is fulfilled (attains the value TRUE),
will be evaluated and, if evaluated TRUE,
event will be evaluated at any time. If an
is evaluated TRUE does the SLC execute
event / action
. When the last
event [1] / action [1]
. The illustra-
:
MG.33.B9.22 - VLT
event
(see par. 13-51) is evaluated as
action [1] is executed. After this, the conditions of
action [2]
will be executed and so on. Events
event is evaluated as FALSE, nothing happens
events
event [1] event [1]
(and only
action [1]
and start evaluating
events
has
events /
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FC 300 Design Guide
will be evaluated. This means
) each scan interval. Only when
event [2]
.