Rockwell Automation 25-COMM-P PowerFlex PROFIBUS DPV1 Adapter - Manual (Page 43)

Rockwell Automation Publication 520COM-UM004A-EN-E - November 2013 43
Using the I/O Chapter 5
P044 [Maximum Freq] . PowerFlex 520-Series Drive Example Speed Reference/
Feedback Scaling on page 43 shows example References and their results for a
PowerFlex 520-series drive that has its:
•
Host parameter P043 [Minimum Freq] set to 10.00 Hz.
•
Host parameter P044 [Maximum Freq] set to 50.00 Hz.
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 a PROFIBUS DPV1 Service. When enabled, each Datalink
occupies one 16-bit word in a ControlLogix, CompactLogix, or MicroLogix
controller, providing a mirror of the PowerFlex 520-series drive data value that
the Datalinked parameter represents.
The following rules apply when using PowerFlex 520-series drive Datalinks:
• The target of a Datalink can be any appropriate Host parameter. For
example,
Host parameter P041 [Accel Time 1] can be the target of the
adapter installed in the drive.
• The data passed through the drive’s Datalink mechanism is determined by
the settings of the following parameters
–
Host parameters C161...C164 [Opt Data In 1...4]
–
Host parameters C165...C168 [Opt Data Out 1...4]
• 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 inactive.
• When you use a Datalink to change a value, the value is not written to the
Non-Volatile Storage (NVS). 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 are locked when the adapter has an I/O connection with a controller.
When a controller has an I/O connection to the adapter, the drive does not allow
a reset to defaults, configuration download or anything else that could change the
PowerFlex 520-Series Drive Example Speed Reference/Feedback Scaling
Network Reference Value Speed Commanded Value Output Speed Network Feedback Value
10000 100.00 Hz 50.00 Hz
(1)
(1) The drive runs at 50.00 Hz instead of 100.00 Hz or 65.00 Hz because Host parameter P044 [Maximum Freq] sets 50.00 Hz as the
maximum speed.
5000
6500 65.00 Hz 50.00 Hz
(1)
5000
3250 32.50 Hz 32.50 Hz 3250
0 0.00 Hz 0.00 Hz 0
IMPORTANT Attempting to write a negative value to the Speed Reference will result in the
drive ramping to maximum speed due to overflow, the direction of the drive
can only be controlled programmatically with the appropriate bits (bits 4 and
5) in the Command Word.