Dynamic Braking; Dc Braking; Sleep Mode; Run Permissive - Danfoss VLT AQUA Drive FC 202 Design Manual

Product Overview
to control multiple motors. The active set-up is displayed
on the LCP.
Setup data can be copied from frequency converter to
frequency converter by downloading the information from
the removable LCP.

2.6.11 Dynamic Braking

Dynamic Brake is established by:
•
Resistor brake
A brake IGBT keeps the overvoltage under a
certain threshold by directing the brake energy
from the motor to the connected brake resistor
(2-10 Brake Function = [1]).
•
AC brake
The brake energy is distributed in the motor by
changing the loss conditions in the motor. The
AC brake function cannot be used in applications
with high cycling frequency since this overheats
the motor (2-10 Brake Function = [2]).

2.6.12 DC Braking

Some applications may require braking a motor to slow or
stop it. Applying DC current to the motor brakes the
motor and can eliminate the need for a separate motor
brake. DC braking can be set to activate at a
predetermined frequency or upon receiving a signal. The
rate of braking can also be programmed.

2.6.13 Sleep Mode

Sleep mode automatically stops the motor when demand
is low for a specified period of time. When the system
demand increases, the converter restarts the motor. Sleep
mode provides energy savings and reduces motor wear.
Unlike a setback clock, the converter is always available to
run when the preset wake-up demand is reached.

2.6.14 Run Permissive

The converter can wait for a remote system ready signal
before starting. When this feature is active, the converter
remains stopped until receiving permission to start. Run
permissive ensures that the system or auxiliary equipment
is in the proper state before the converter is allowed to
start the motor.
MG20N602
Design Guide

2.6.15 Smart Logic Control (SLC)

Smart logic control (SLC) is a sequence of user-defined
actions (see 13-52 SL Controller Action [x]) executed by the
SLC when the associated user defined event (see 13-51 SL
Controller Event [x]) is evaluated as TRUE by the SLC.
The condition for an event can be a particular status or
that the output from a logic rule or a comparator operand
becomes TRUE. That leads to an associated action as
shown in Illustration 2.19.
Par. 13-51
SL Controller Event
Running
Warning
Torque limit
Digital input X 30/2
. . .
Par. 13-43
Logic Rule Operator 2
. . .
. . .
Par. 13-11
Comparator Operator
=
TRUE longer than..
. . .
. . .
Illustration 2.19 SCL Event and Action
Events and actions are each numbered and linked in pairs
(states). This means that when event [0] is fulfilled (attains
the value TRUE), action [0] is executed. After this, the
conditions of event [1] is evaluated and if evaluated TRUE,
action [1] is executed and so on. Only one event is
evaluated at any time. If an event is evaluated as FALSE,
nothing happens (in the SLC) during the current scan
interval and no other events are evaluated. This means that
when the SLC starts, it evaluates event [0] (and only event
[0]) each scan interval. Only when event [0] is evaluated
TRUE, the SLC executes action [0] and starts evaluating
event [1]. It is possible to programme from 1 to 20 events
and actions.
When the last event/action has been executed, the
sequence starts over again from event [0]/action [0].
Illustration 2.20 shows an example with 4 event/actions:
Danfoss A/S © 09/2014 All rights reserved.
2
Par. 13-52
SL Controller Action
Coast
Start timer
Set Do X low
Select set-up 2
. . .
31
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