Current Monitoring And Limits; Direction Of Rotation; Start/Stop; Freeze Mode - Danfoss VLT 6000 Manual

Current Monitoring and Limits (19, 30)

The maximum current that the drive provides to the
motor can be limited. This tends to limit the torgue
that can be produced by the motor. Data point 30
sets the current limit in amps, while data point 19
indicates if the motor is operating at that current
limit.

Direction of Rotation (21-22)

The drive responds to serial commands to reverse
direction of the motor. The drive can safely reverse
motor rotation while in operation. Many applications
benefit from this ability, such as vane axial fans
reversed for smoke extraction or cooling towers for
deicing. Parameter 506, Reversing, must be set to
serial communication for point 22 to command the
feature.

Start/Stop (23, 24)

To run the drive from the FLN or in Auto mode from
the drive's digital control terminals, a start command
must be given at data point 24. When a stop
command is given at this point, the drive will only run
in Hand mode.

Freeze Mode (25, 26)

If desired, the frequency of the drive can be frozen
at its present value. The mode is indicated by data
point 25. It is an option available when serial
interface is lost.

Coast (27, 28)

The coast command (28) shuts down the inverter
and makes the motor freewheeling, which normally
brings it to stand still. The drive cannot be restarted
in any mode before the coast command is removed.
It is, therefore, often used as a safety interlock. Data
point 27 indicates when the drive is coasted.

Motor Ramp-up and Ramp-down Rate (31, 32)

The time to accelerate or decelerate the drive
between 0 Hz and the motor's nominal frequency
can be programmed. The drive is capable of settings
between one to 3600 seconds (one hour).

Lock Panel (33)

The local control panel on the VLT 6000 drive can be
locked to ensure that program data or drive control
functions cannot be changed locally. The Stop but-
ton on the keypad will also be locked out and be
incapable of stopping the drive. The serial interface
continues to access drive settings.
MG.60.G2.02 - VLT is a registered Danfoss Trademark
VLT ® 6000 HVAC

Hand/Auto Modes (34)

The SEL HND.AUTO shows which mode the drive is
in. The drive can be commanded into either Hand or
Auto mode by pressing the respective keys on the
keypad of the drive. Hand mode disables any pro-
grammed control strategies and allows the drive
keypad to be used to set the drive speed. The only
serial communication command that can override
Hand mode is data point 28, CMD COAST.

Run Enable (35)

Set data point 35 to ON to run the drive from the
FLN with default drive parameter settings. In the OFF
mode, the drive will run only in Hand mode or in Auto
mode from the drive's digital control terminals.
Parameter 505, Start, controls the interaction of
point 35 and the digital run command.

Bus Functions (36, 37)

The amount of time the drive will wait between
communication packets is programmable. If the time
is exceeded, the drive will assume serial communica-
tion has stopped and respond with programmable
choices. The drive can ignore the loss, freeze its
current output, stop, run at a predetermined jog
frequency, run at maximum output frequency or stop
and trip while issuing an alarm. Wait time is selected
at point 36 and the function after a timeout at point
37. See descriptions for parameters 565, FLN Bus
Time Interval and 566, FLN Bus Time Interval
Function in the VLT 6000 Operating Instructions.

Frequency Out High, Low Limits (38, 39)

Limits to the maximum and minimum drive output
frequency are programmable. For example, pump
manufacturers typically recommend not to opera-
te pumps below a certain speed (for example, 15 Hz)
to avoid seal problems.
Relay Out 1, 2 (40, 41, 43, 44)
Two programmable relay outputs (one Form C, 240
VAC, 2 Amp; and one Form A, 30 VAC, 1 Amp) are
available. These can be triggered through the serial
bus by command points 40 and 41. This allows the
FLN to utilize the drive's built-in relays as additional
network programmable relays. The data points 43
and 44 indicate whether the relay is triggered or not
(On/Off). Parameters 323 and 326, Relay 1 and
Relay 2 Output Function, must be set to CONTROL
WORD 11/12.
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