Rockwell Automation 20D PowerFlex 700S AC Drives with Phase II Control Reference Manual - Manual (Page 80)

80 Rockwell Automation Publication PFLEX-RM003E-EN-E - January 2011
Chapter 1 Detailed Drive Operation
Example:
• Link parameter 213 [PkDtct1 In Real] to parameter 300 [Motor Spd
Fdbk].
• Verify that parameter 210 [PeakDtct Ctrl In], bit 0 “Peak 1 Set” and bit 1
“Peak 1 Hold” are set to 0.
• For parameter 210 [PeakDtct Ctrl In], set bit 2 “Peak1SelHigh” = 1.
• Parameter 215 [PeakDetect1 Out] will contain the positive peak value of
[Motor Spd Fdbk].
• To reset the output of the peak detector, for parameter 210 [PeakDtct Ctrl
In], toggle on and then off bit 0 “Peak 1 Set”.
Permanent Magnet Motors See Appendix D of the PowerFlex 700S AC Drive Phase II Control - Programming
Manual, publication 20D-PM001 , for details on permanent magnet motors
compatible with PowerFlex 700S Phase II drives.
Phase Locked Loop Many processes are driven by a mechanical line shaft with an intermediate gear-
box or take-off point to the load. That way a precise phase or position can be
maintained from one mechanical structure to another. A printing press is a good
example. Each color applied must precisely be overlaid to hold registration and
the system must be locked in phase to accomplish that task. The trouble with the
mechanical system is that it wears with time and is inflexible. Replacing the
mechanical line shaft with an Electronic Line Shaft (ELS) saves the cost of
maintenance while providing the flexibility to re-configure the system.
There are two fundamental configurations of an ELS:
1. Virtual Master Reference
A virtual master reference electronically generates and sends position and
speed references to all follower drives. Each drive is electronically position
locked to a virtual reference generated by a Virtual Encoder (VE). There is
no physical shaft or encoder to generate the reference.
2. Real Master Reference
A real master reference generates and sends position and speed references
from an encoder attached to a physical shaft. The encoder signal must first
be conditioned to account for a number of issues before being sent.
The Phased Locked Loop (PLL) is used to condition the master encoder and re-
generate the encoder signal so that it can be used as a master reference for the