Rockwell Automation 20D PowerFlex 700S AC Drives with Phase II Control Reference Manual - Manual (Page 148)

148 Rockwell Automation Publication PFLEX-RM003E-EN-E - January 2011
Chapter 1 Detailed Drive Operation
Stop Command
When a stop command is issued, parameter 157 [Logic Ctrl State], bit 0 “Spd Ref
En” is set to “0”, causing a zero speed to be selected. When [Logic Ctrl State], bit 0
is set to “1” the selected speed or jog reference is used.
Accel/Decel Ramp and S-Curve
Parameter 32 [Accel Time 1] sets the acceleration time in seconds from 0 speed
to the speed in parameter 4 [Motor NP RPM]. Parameter 33 [Decel Time 1] sets
the deceleration time in seconds from the speed in parameter 4 [Motor NP
RPM] to 0. The ramp rate in RPM/sec can be determined. For example, the ramp
rate for acceleration would be [Motor NP RPM]/[Accel Time].
The ramped reference can be viewed in parameter 43 [Ramped Spd Ref ].
The accel/decel ramp generator can be bypassed for certain functions. When
parameter 151 [Logic Command], bit 0 “SpdRamp Dsbl” = 1, the ramp is
bypassed.
The output of the accel/decel ramp can also be held at its present value by setting
parameter 151 [Logic Command], bit 4 “SpdRamp Hold” = 1.
The drive can produce a linear or S-curve ramp output signal. The S-curve ramp
is used when parameter 151 [Logic Command], bit 1 “Spd S Crv En” is on and
the ramp is not bypassed. Parameter 34 [S Curve Time] sets the time, in seconds,
that the S-curve will be applied at the beginning and at the end of the ramp. Half
of the time specified in parameter 34 is added to the beginning of the ramp and
32
33
34
&
41
S Curve Time
Accel Time 1
Decel Time 1
Logic Ctrl State
From Speed
Reference Limits
(SRef Ramp En)
Logic Ctrl State
(SRef SCrv En)
157 02
157 01
43
Ramped Spd Ref
Ramp
S Curve
Logic Command
(SpdRamp Hold)
151 04
Logic Command
(SpdRamp Dsbl)
Logic Command
(Spd S Crv En)
151 00
151 01
Inv
Limited Spd Ref