Rockwell Automation 20D PowerFlex 700S AC Drives with Phase II Control Reference Manual - Manual (Page 145)

Rockwell Automation Publication PFLEX-RM003E-EN-E - January 2011 145
Detailed Drive Operation Chapter 1
Manual Speed Feedback Device Switching
Parameter 151 [Logic Command], bit 2 “TackLoss Rst”, provides a manual
switch between active and non-active primary or alternate speed feedback devices
with a “0” to “1” bit transition. Resetting bit 2 from a “1” to a “0” causes no
change in operation. The switch is from the active feedback device (either
primary or alternate) to the non-active feedback device. For example, if prior to
the reset the alternate device selected in Parameter 223 [Mtr Fdbk Sel Alt] is
active, then after the reset the primary feedback device selected in Parameter 222
[Mtr Fdbk Sel Pri] will be used as the active speed feedback device. The reset
activation is prohibited if a failure is sensed in the speed feedback device to which
the drive is switching. The active device selection command is shown in
parameter 152 [Applied LogicCmd]. Manual switching between primary and
alternate devices can be made while the drive is running.
Speed Reference The speed reference control loop consists of speed reference selection, scaling
jogging, limiting, ramping, S-curve, and filtering. Each part of the speed
reference loop is explained in this section.
Speed Reference Selection
The selection of the active speed reference can be made through digital inputs,
DPI (communication) command or DriveLogix. The input selected by any of
these sources is show in parameter 152 [Applied LogicCmd], bits 28 “Spd Ref
Sel0”, 29 “Spd Ref Sel1”, and 30 “Spd Ref Sel2”.
Table 23 (below) shows the truth
table for the selected speed reference based on Spd Ref Sel0, 1, and 2 and
Figure 23 on page 146 shows the diagram for the selected speed reference.
Table 23 - Speed Reference Select Inputs
Note: to use Preset Speed 1, program parameter 27 [Speed Ref A Sel] or 28
[Speed Ref B Sel] = 5 “Preset Spd 1.”
2 1 0 Auto Reference Source
0 0 0 Reference A
0 0 1 Reference B
0 1 0 Preset Speed 2
0 1 1 Preset Speed 3
1 0 0 Preset Speed 4
1 0 1 Preset Speed 5
1 1 0 Preset Speed 6
1 1 1 Preset Speed 7