Emerson unidrive sp User Manual page 225

Safety Mechanical
Product
Information information Installation
Preset references
Preset references 1 to 8 are contained in Pr 1.21 to Pr 1.28.
Keypad reference
If Keypad reference is selected the drive sequencer is controlled directly
by the keypad keys and the keypad reference parameter (Pr 1.17) is
selected. The sequencing bits, Pr 6.30 to Pr 6.34, and Pr 6.37 have no
effect and jog is disabled.
Precision reference
If Precision reference is selected the speed reference is given Pr 1.18
and Pr 1.19.
11.21.2 Braking Modes
2.04 Ramp mode select
RW Txt
FASt (0), Std (1),
OL
Std.hV (2)
CL FASt (0), Std (1)
This parameter does not affect the acceleration ramp, as the ramp
output always rises at the programmed acceleration rate subject to the
current limits. It is possible in under some unusual circumstances in
open-loop mode (i.e. highly inductive supply) for the motor to reach a low
speed in standard ramp mode, but not completely stop. It is also
possible if the drive attempts to stop the motor with an overhauling load
in any mode that the motor will not stop when standard ramp mode or
fast ramp mode is used. If the drive is in the deceleration state the rate of
fall of the frequency or speed is monitored. If this does not fall for 10
seconds the drive forces the frequency or the speed reference to zero.
This only applies when the drive is in the deceleration state and not
when the reference is simply set to zero.
0: Fast ramp
Fast ramp is used where the deceleration follows the programmed
deceleration rate subject to current limits.
1: Standard ramp
Standard ramp is used. During deceleration, if the voltage rises to the
standard ramp level (Pr 2.08) it causes a controller to operate, the output
of which changes the demanded load current in the motor. As the
controller regulates the link voltage, the motor deceleration increases as
the speed approaches zero speed. When the motor deceleration rate
reaches the programmed deceleration rate the controller ceases to
operate and the drive continues to decelerate at the programmed rate. If
the standard ramp voltage (Pr 2.08) is set lower than the nominal DC
Bus level the drive will not decelerate the motor, but it will coast to rest.
The output of the ramp controller (when active) is a current demand that
is fed to the frequency changing current controller (Open-loop modes) or
the torque producing current controller (Closed-loop vector or Servo
modes). The gain of these controllers can be modified with Pr 4.13 and
Pr 4.14.
Controller
operational
Motor Speed
Programmed
deceleration
rate
Unidrive SP Free Standing User Guide
Issue Number: 1
Electrical Getting Basic Running the
Installation Started parameters
US
Std (1)
DC Bus voltage
t
www.controltechniques.com
SMARTCARD
Optimization
motor operation
2: Standard ramp with motor voltage boost
This mode is the same as normal standard ramp mode except that the
motor voltage is boosted by 20%. This increases the losses in the motor
giving faster deceleration.
2.08 Standard ramp voltage
RW Uni
0 to
DC_VOLTAGE_SET_MAX V
This voltage is used as the control level for standard ramp mode. If this
parameter is set too low the machine will coast to rest, and if it is set too
high and no braking resistor is used the drive may give an over-volt 'OV'
trip. The minimum level should be greater than the voltage produced on
the DC Bus by the highest supply voltage. Normally the DC Bus voltage
will be approximately the rms supply line voltage x √2.
Care should be taken in the setting of this parameter. It is
recommended that the setting should be at least 50V higher
than the maximum expected level of the DC Bus voltage. If
this is not done, the motor may fail to decelerate on a STOP
WARNING command.
11.21.3 S ramps
2.06 S ramp enable
RW Bit
OFF (0) or On (1)
Setting this parameter enables the S ramp function. S ramp is disabled
during deceleration using standard ramp. When the motor is accelerated
again after decelerating in standard ramp the acceleration ramp used by
the S ramp function is reset to zero.
2.07 S ramp acceleration limit
RW Uni
0.0 to 300.0
OL
2
s /100Hz
VT
0.000 to 100.000
2
s /1000rpm
SV
This parameter defines the maximum rate of change of acceleration/
deceleration. The default values have been chosen such that for the
default ramps and maximum speed, the curved parts of the S will be
25% of the original ramp if S ramp is enabled.
Technical
Onboard Advanced
Diagnostics
PLC parameters Data
RA
200V drive: 375
400V drive: EUR> 750
575V drive: 895
690V drive: 1075
OFF (0)
1.500
0.030
UL Listing
Information
US
USA> 775
US
US
3.1
225