Rockwell Automation 20-750-CNETC PowerFlex Coaxial ControlNet Option Module - Manual (Page 64)

64 Rockwell Automation Publication 750COM-UM003B-EN-P - November 2012
Chapter 5 Using the I/O
When Parameter 300 - [Speed Units] is set to RPM, the other parameters are also
in RPM.
Table 3 - PowerFlex 750-Series Drive Example Speed Reference/Feedback Scaling
Using Datalinks A Datalink is a mechanism used by PowerFlex drives to transfer data to and from
the controller. Datalinks allow a drive parameter value to be read or written to
without using an Explicit Message. When enabled, each Datalink occupies one
32-bit word in a ControlLogix controller.
The following rules apply when using PowerFlex 750-Series drive Datalinks:
• The target of a Datalink can be any
Host parameter, including those of a
peripheral. For example, drive parameter 535 - [Accel Time 1] can be the
target of any or all option modules installed in the drive.
• The data passed through the drive’s Datalink mechanism is determined by
the settings of
Host Parameters 01…16 - [DL From Net 01-16] and Host
Parameters 17…32 - [DL To Net 01-16] .
• When an I/O connection that includes Datalinks is active, those Datalinks
being used are locked and cannot be changed until that I/O connection
becomes idle or inactive.
• When you use a Datalink to change a value, the value is not written to the
Nonvolatile Storage (NVS) memory. The value is stored in volatile
memory and lost when the drive loses power. Thus, use Datalinks when
you need to change a value of a parameter frequently.
Datalinks for PowerFlex 750-Series drive peripherals (the embedded EtherNet/
IP adapter on PowerFlex 755 drives only, and option modules such as an encoder
or a communication module) are locked when the peripheral has an I/O
connection with a controller. When a controller has an I/O connection to the
drive, the drive does not allow a reset to defaults, configuration download, or
Network Reference Value Speed Command Value
(2)
(2) For this example, drive parameter 300 - [Speed Units] is set to Hz.
Output Speed Network Feedback Value
130.0 130 Hz 60 Hz
(3)
(3) The drive runs at 60 Hz instead of 130 Hz or 65 Hz because drive Parameter 520 - [Max Fwd Speed] sets 60 Hz as the maximum
speed.
60.0
65.0 65 Hz 60 Hz
(3)
60.0
32.5 32.5 Hz 32.5 Hz 32.5
0.0 0 Hz 0 Hz 0.0
-32.5
(1)
(1) The effects of values less than 0.0 depend on whether the PowerFlex 750-Series drive uses a bipolar or unipolar direction mode. See
the drive documentation for details.
32.5 Hz 32.5 Hz 32.5
IMPORTANT A reset is always required after configuring Datalinks so that the
changes take effect.