High And Low Reference Warning; High And Low Feedback Warning; Phase Imbalance Or Phase Loss; High Frequency Warning - Danfoss VLT AQUA Drive FC 202 Design Manual

Product Overview

2.7.2 High and Low Reference Warning

2 2
In open-loop operation, the reference signal directly
determines the speed of the drive. The display shows a
flashing reference high or low warning when the
programmed maximum or minimum is reached.

2.7.3 High and Low Feedback Warning

In closed-loop operation, the selected high and low
feedback values are monitored by the drive. The display
shows a flashing high or flashing low warning when
appropriate. The drive can also monitor feedback signals in
open-loop operation. While the signals do not affect the
operation of the drive in open-loop, they can be useful for
system status indication locally or via serial communi-
cation. The adjustable frequency drive handles 39 different
units of measure.

2.7.4 Phase Imbalance or Phase Loss

Excessive ripple current in the DC bus indicates either a
line phase imbalance or phase loss. When a power phase
to the drive is lost, the default action is to issue an alarm
and trip the unit to protect the DC bus capacitors. Other
options are to issue a warning and reduce output current
to 30% of full current or to issue a warning and continue
normal operation. Operating a unit connected to an
imbalanced line may be desirable until the imbalance is
corrected.

2.7.5 High Frequency Warning

Useful in staging on additional equipment such as pumps
or cooling fans, the drive can warm when the motor speed
is high. A specific high frequency setting can be entered
into the drive. If the output exceeds the set warning
frequency, the unit displays a high frequency warning. A
digital output from the drive can signal external devices to
stage on.

2.7.6 Low Frequency Warning

Useful in staging off equipment, the drive can warn when
the motor speed is low. A specific low frequency setting
can be selected for warning and to stage off external
devices. The unit will not issue a low frequency warning
when it is stopped nor upon start up until after the
operating frequency has been reached.
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VLT AQUA Drive FC 202

2.7.7 High Current Warning

This function is similar to high frequency warning, except a
high current setting is used to issue a warning and stage
on additional equipment. The function is not active when
stopped or at start up until the set operating current has
been reached.

2.7.8 Low Current Warning

This function is similar to low frequency warning (see
chapter 2.7.6 Low Frequency Warning), except a low current
setting is used to issue a warning and stage off equipment.
The function is not active when stopped or at start up
until the set operating current has been reached.

2.7.9 No Load/Broken Belt Warning

This feature can be used for monitoring a no-load
condition, for example a V-belt. After a low current limit
has been stored in the converter, if loss of the load is
detected, the drive can be programmed to issue an alarm
and trip or to continue operation and issue a warning.

2.7.10 Lost Serial Interface

The adjustable frequency drive can detect loss of serial
communication. A time delay of up to 99 s is selectable to
avoid a response due to interruptions on the serial
communications bus. When the delay is exceeded, options
available include for the unit to:
•
•
•
•

2.8 User Interfaces and Programming

The adjustable frequency drive uses parameters for
programming its application functions. Parameters provide
a description of a function and a menu of options to either
select from or for entering numeric values. A sample
programming menu is shown in Figure 2.23.
Danfoss A/S © 09/2014 All rights reserved.
Maintain its last speed.
Go to maximum speed.
Go to a preset speed.
Stop and issue a warning.
MG20N622