VLT
®
4000 VT
Programming
206 Ramp-up time
(RAMP UP TIME)
Value:
1 - 3600 sec.
✭
Depends on the unit
Function:
The ramp-up time is the acceleration time from 0
Hz to the rated motor frequency f
M,N
(parameter
104
Motor frequency, f
M,N
). It is assumed that the
output current does not reach the current limit (set
in parameter 215
Current limit I
LIM
).
Description of choice:
Program the desired ramp-up time.
207 Ramp-down time
(RAMP DOWN TIME)
Value:
1 - 3600 sec.
✭
Depends on the unit
Function:
The ramp-down time is the deceleration time
from the rated motor frequency f
M,N
(parameter
104
Motor frequency, f
M,N
) to 0 Hz, provided
there is no overvoltage in the inverter because of
the motor acting as a generator.
Description of choice:
Program the desired ramp-down time.
208 Automatic ramp-down
(AUTO RAMPING)
Value:
Disable (DISABLE)
[0]
✭
Enable (ENABLE)
[1]
Function:
This function ensures that the AFD does not trip
during deceleration if the ramp-down time set is too
short. If, during deceleration, the AFD registers that
the intermediate circuit voltage is higher than the
max. value (see
list of warnings and alarms
), the AFD
automatically extends the ramp-down time.
NOTE
If the function is chosen as
Enable
[1], the ramp
time may be considerably extended in relation to
the time set in parameter 207
Ramp-down time
.
Description of choice:
Program this function as
Enable
[1] if the AFD
periodically trips during ramp-down. If a quick
ramp-down time has been programmed that may
lead to a trip under special conditions, the function
can be set to
Enable
[1] to avoid trips.
209 Jog frequency
(JOG FREQUENCY)
Value:
Par. 201
Output frequency Low limit
- par. 202
Output frequency high limit
✭
10.0 HZ
Function:
The jog frequency f
JOG
is the fixed output
frequency at which the AFD is running when
the jog function is activated.
Jog can be activated via the digital inputs.
Description of choice:
Set the desired frequency.
■
Reference type
The example shows how the resulting reference is
calculated when Preset references are used together
with Sum and Relative in parameter 210 Reference
type. See
Calculation of resulting reference
. See
also the drawing in
Reference handling
.
The following parameters have been set:
Par. 204
Minimum reference:
10 Hz
Par. 205
Maximum reference:
50 Hz
Par. 211
Preset reference:
15%
Par. 308
Terminal 53, analog input:
Reference [1]
Par. 309
Terminal 53, min. scaling:
0 V
Par. 310
Terminal 53, max. scaling:
10 V
When parameter 210
Reference type
is set to Sum
[0], one of the adjusted
Preset references
(par. 211-
MG.40.A7.22 - VLT is a registered Danfoss trademark
77