Danfoss VT2800 Series Design Manual page 89

NB!:
If Freeze output is acti v e the frequency converter
can only be stopped if you select Motor coast,
Quick stop or DC braking via a digital input.
Speed up and Speed down are selected if digital
control of the up/down speed is required. This
function is only acti v e if Freeze reference or Freeze
output frequency has been selected.
If Speed up is acti v e the reference or output frequency
will be increased, and if Speed down is acti v e the
reference or output frequency will be reduced. The
output frequency is changed via the preset ramp
times in parameters 209-210 Ramp 2.
One pulse (logic '1' minimum high for 14 ms
and a minimum break time of 14 ms) will lead
to a speed change of 0.1 % (reference) or 0.1
Hz (output frequency). Example:
Term. Term. Freeze ref/
29 33 freeze outp.
0 0 1
0 1 1
1 0 1
1 1 1
Freeze reference can be changed even if the frequency
converter has stopped. The reference will also be
saved if the mains are disconnected.
Catch-up/Slow-down is selected if the reference
value is to be increased or reduced by a
programmable percentage value set in parameter
219 Catch-up/Slow-down reference .
Slow-down Catch-up
0 0
0 1
1 0
1 1
Ramp 2 is selected if a shift between ramp 1
(parameters 207-208) and ramp 2 (parameters
209-210) is required. Logic '0' leads to ramp
1 and logic '1' leads to ramp 2.
Preset reference, lsb and Preset reference, msb
makes it possible to select one of the four preset
references, see the table below:
Preset ref. Preset ref.
msb lsb
0 0
0 1
1 0
1 1
= factory setting. () = display text [] = value for use in communication via serial communication port
MG.28.E9.02 - VLT is a registered Danfoss trademark
Function
No speed change
Speed up
Speed down
Speed down
Function
Unchanged speed
Increase by % value
Reduce by % value
Reduce by % value
Function
Preset ref. 1
Preset ref. 2
Preset ref. 3
Preset ref. 4
®
VLT 2800 Series
Preset reference on is used for shifting between
remote-controlled reference and preset reference.
It is assumed that External/preset [2] has been
selected in parameter 214 Reference function. Logic
'0' = remote-controlled references are acti v e, logic
'1' = one of the four preset references is acti v e,
as can be seen from the table above.
Thermistor is to be selected if a possibly integrated
thermistor in the motor is to be able to stop
the frequency converter if the motor overheats.
The cut-out value is 3 k .
If a motor features a Klixon thermal switch instead, this
can also be connected to the input. If motors operate
in parallel, the thermistors/thermal switches can be
connected in series (total resistance lower than 3 k ).
Parameter 128 Motor thermal protection must be
programmed for Thermistor warning [1] or Thermistor
trip [2] and the thermistor is to be connected between
a digital input and terminal 50 (+ 10 V supply).
Precise stop, inverse is selected to obtain a high
degree of accuracy when a stop command is
repeated. A logic 0 means that the motor speed is
ramped down to stop via the selected ramp.
Precise start/stop is selected to obtain a high degree of
accuracy when a start and stop command is repeated.
Pulse reference is selected if the reference
signal applied is a pulse train (frequency). 0 Hz
corresponds to parameter 204 Minimum reference,
Ref . The frequency set in parameter 327 Pulse
MIN
reference/feedback corresponds to parameter
205 Maximum reference Ref
Pulse feedback is selected if the feedback signal
used is a pulse train (frequency). In parameter
.
MAX
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