Coarse update rate, Motion drive start (mds) instruction – Rockwell Automation 20G PowerFlex 750-Series AC Drives User Manual
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Rockwell Automation Publication 750-RM002B-EN-P - September 2013
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Integrated Motion on the EtherNet/IP Network Applications for PowerFlex 755 AC Drives
Chapter 6
Coarse Update Rate
The position loop for the PowerFlex 755 drive is updated at a rate of 1.024 ms
(1024
µsec). During each position loop update the drive can either read or write
data to the embedded Ethernet port, but cannot do both operations during the
same update. Therefore the drive can receive only new updates every other
position loop update event. To read new information from the Motion Planner
(that is controller), the minimum coarse update rate must be 2.5 ms or greater to
be sure that no data packets are lost. If the PowerFlex 755 drive is operated at a
coarse update rate of less than 2.5 ms, data packets can be lost (resulting in the
drive interpolating between missed updates), and/or the drive can fault if enough
data packets are missed consecutively. Rockwell Automation recommends a
minimum coarse update rate of 3 ms for the PowerFlex 755 drive.
Control Modes for PowerFlex
755 Drives Operating on the
Integrated Motion on the
EtherNet/IP Network
Integrated Motion on the EtherNet/IP network is a feature available with
firmware revision 2.xxx and later for PowerFlex 755 drives. This feature provides
a common user experience as with Kinetix 6500 drives when used with Logix
controllers, revision 19 and later, on the EtherNet/IP network:
•
The same motion profile provides a common configuration experience.
The PowerFlex 755 drive uses the Motion Properties/Axis Properties and
the same motion attributes as the Kinetix 6500 drive.
•
The same motion instructions provide a common programming
experience.
Refer to the Integrated Motion on EtherNet/IP appendix in the PowerFlex 750-
Series Programming Manual, publication
, for more information.
Motion Drive Start (MDS) Instruction
For information regarding the MDS instruction, refer to the Logix5000
Controllers Motion Instructions Reference Manual, publication
.
For the PowerFlex 755 drive, the MDS instruction is valid only when the axis
configuration is set to one of these control modes:
•
Frequency Control
•
Velocity Loop
•
Torque Loop
The MDS instruction is not valid when the axis configuration is set to Position
Loop.