Danfoss VLT 2800 Design Manual page 87

Programming
transistors are turned off), which means that the motor
runs freely to stop. Logic '0' leads to coasting to stop.
Reset and coasting inverse are used to activate motor coast
simultaneously with reset. Logical '0' means motor coast
stop and reset. Reset is activated on the falling edge.
Quick stop inverse is used for activating the quick-stop
ramp down set in parameter 212 Quick stop ramp-down
time. Logic '0' leads to quick stop.
DC-braking inverse is used for stopping the motor by
energising it with a DC voltage for a given time, see
parameters 126, 127 and 132 DC brake. Note that this
function is only active if the value in parameters 126 DC
braking time and 132 DC brake voltage is different from 0.
Logic '0' leads to DC braking.
Stop inverse, a logic '0' means that the motor speed is
ramped down to stop via the selected ramp.
Select Start if a start/stop command is required. Logic '1' =
start, logic '0' = stop.
Illustration 4.13 Start and Stop Commands
Latched start, if a pulse is applied for mininum 14 ms, the
frequency converter starts the motor, provided no stop
command has been given. The motor can be stopped by
briefly activating Stop inverse.
Select Reversing to change the direction of rotation of the
motor shaft. Logic '0' does not lead to reversing. Logic '1'
leads to reversing. The reverse signal only changes the
direction of rotation, it does not activate the start. Is not
active at Process regulation, closed loop. See also
chapter 4.3.1 Output frequency range parameter 200.
Reversing and start is used for start/stop and for reversing
with the same signal. No active start command is allowed
at the same time. Acts as latch start reversing, provided
latch start has been selected for terminal 18. Is not active
for Process regulation, closed loop. See also
chapter 4.3.1 Output frequency range parameter 200.
MG27E402
Design Guide
Use Start clockwise to configure the motor to only rotate
clockwise when started. Should not be used for Process
regulation, closed loop.
Use Start anticlockwise to configure the motor to rotate
counter-clockwise when started. Should not be used for
Process regulation, closed loop. See also chapter 4.3.1 Output
frequency range parameter 200.
Jog is used to override the output frequency to the jog
frequency set in parameter 213 Jog frequency. Jog is active
regardless of whether a start command has been given,
yet not when Coast stop, Quick-stop or DC braking are
active.
Freeze reference freezes the present reference. The
reference can now only be changed via Speed up and
Speed down. If freeze reference is active, it is saved after a
stop command and in the event of mains failure.
Freeze output freezes the present output frequency (in Hz).
The output frequency can now only be changed via Speed
up and Speed down.
Speed up and Speed down are selected if digital control of
the up/down speed is required. This function is only active
if Freeze reference or Freeze output frequency has been
selected.
If Speed up is active, the reference or output frequency is
increased, and if Speed down is active the reference or
output frequency is 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) leads to a speed change of
0.1 % (reference) or 0.1 Hz (output frequency).
Term.
29
0
0
1
1
Table 4.3 Speed-up and Speed-down Functions
Freeze reference can be changed even if the frequency
converter has stopped. The reference is also 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
0
0
1
1
Table 4.4 Slow-down and Catch-up Functions
Danfoss A/S © Rev. May/2014 All rights reserved.
Term. Freeze ref/freeze
33 outp.
0 1 No speed change
1 1 Speed up
0 1 Speed down
1 1 Speed down
Catch-up
0 Unchanged speed
1 Increase by % value
0 Reduce by % value
1 Reduce by % value
4
Function
Function
85
4