S Ramp Enable; S Ramp Acceleration Limit - Control Techniques unidrive sp Advanced User's Manual

Parameter Keypad and Parameter
structure display x.00
Controller
operational
Motor Speed
Programmed
deceleration
rate
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.
2.06

S ramp enable

Drive modes Open-loop, Closed-loop vector, Servo
Bit SP
Coding
1
Default Open-loop, Closed-loop vector, Servo
Update rate 4ms read
Setting this parameter enables the S ramp function. S ramp is disabled during deceleration when the standard ramp voltage controller is active. 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

Drive modes Open-loop, Closed-loop vector, Servo
Bit SP
Coding
Closed-loop vector and Servo DP = 3
Open-loop
Range
Closed-loop vector and servo
Open-loop
Default Closed-loop vector
Servo
Update rate Background read
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.
Demanded Speed
Acceleration
Actual Speed
Programmed
ramp rate
S ramp
acceleration
ramp
T/2 T/2
T
Since the ramp rate is defined in s/100Hz or s/1000rpm and the S ramp parameter is defined in s
part of the S can be determined from:
T = S ramp rate of change / Ramp rate
Enabling S ramp increases the total ramp time by the period T since an additional T/2 is added to each end of the ramp in producing the S.
Unidrive SP Advanced User Guide
Issue Number: 7
Parameter Advanced parameter
description format descriptions
DC Bus voltage
t
FI DE Txt VM DP ND RA NC NV
0
FI DE Txt VM DP ND RA NC NV
1
0.0 to 300.0 s
0.000 to 100.000 s
3.1
1.500
0.030
T/2 T/2 t
T
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Serial comms Electronic
Macros
protocol nameplate
PT US RW BU PS
1 1
PT US RW BU PS
1 1 1
2
/100Hz
2
/1,000rpm
2
/100Hz or s
Feature look-
Performance Menu 2
up table
2
/1000rpm, the time T for the 'curved'
39