Allen-Bradley PowerFlex 70 Reference Manual

2-58 Datalinks
Datalinks A Datalink is one of the mechanisms used by PowerFlex drives to transfer
data to and from a programmable controller. Datalinks allow a parameter
value to be changed without using an Explicit Message or Block Transfer.
Datalinks consist of a pair of parameters that can be used independently for
16 bit transfers or in conjunction for 32 bit transfers. Because each Datalink
consists of a pair of parameters, when enabled, each Datalink occupies two
16 or 32-bit words in both the input and output image tables, depending on
configuration. A user enters a parameter number into the Datalink
parameter. The value that is in the corresponding output data table word in
the controller is then transferred to the parameter whose number has been
placed in the Datalink parameter. The following example demonstrates this
concept. The object of the example is to change Accel and Decel times “on
the fly” under PLC control.
The user makes the following PowerFlex drive parameter settings:
Parameter 300 [Data In A1] = 140 (the parameter number of [Accel Time 1]
Parameter 301 [Data In A2] = 142 (the parameter number of [Decel Time 1]
In the PLC data Table, the user enters Word 3 as a value of 100 (10.0 Secs)
and word 4 as a value of 133 (13.3 seconds). On each I/O scan, the
parameters in the PowerFlex drive are updated with the value from the data
table:
Accel Time P140 = 10.0 seconds (value from output image table Word 3)
Decel Time P142 = 13.3 seconds (value from output image table Word 4).
Any time these values need to be changed, the new values are entered into
the data table, and the parameters are updated on the next PLC I/O scan.
Programmable
Controller
I/O Image Table
Remote I/O
Communication
Module
Adjustable Frequency
AC Drive
Block Transfer
Logic Command
Analog Reference
WORD 3
WORD 4
WORD 5
WORD 6
WORD 7
Output Image
Data In A1
Data In A2
Data Out A1
Data Out A2
300
301
310
311
Parameter/Number
Block Transfer
Logic Status
Analog Feedback
WORD 3
WORD 4
WORD 5
WORD 6
WORD 7
Input Image
Datalink A
Datalink A

Allen-Bradley PowerFlex 70 Specifications

General

Brand	Allen-Bradley
Model	PowerFlex 70
Category	Controller
Language	English