Rockwell Automation 20-COMM-H RS485 HVAC Adapter FRN 2.xxx - Manual (Page 67)

20-COMM-H RS-485 HVAC Adapter User Manual
Publication 20COMM-UM009D-EN-P
Chapter 7
Using Datalinks with All Protocols
This chapter provides information and examples showing how to use
Datalinks.
Using Datalinks A Datalink is a mechanism used by PowerFlex drives to transfer data to and
from the controller. Datalinks “point” to specific drive parameters to be
accessed. When enabled, each Datalink occupies two 16-bit or two 32-bit
words in both the input and output image. Adapter Parameter 19 -
[Datalink Size] indicates whether the drive uses 16-bit or 32-bit words for
Datalinks.
Rules for Using Datalinks
•
Each set of Datalink parameters in a PowerFlex drive can be used by
only one adapter. If more than one adapter is connected to a single drive,
multiple adapters must not try to use the same Datalink.
•
Parameter settings in the drive determine the data passed through the
Datalink mechanism. Refer to the documentation for your drive.
•
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.
32-Bit Parameters using 16-Bit Datalinks
This subsection only pertains to PowerFlex 70 (SC or EC), PowerFlex 700
(SC), and PowerFlex 700H drives which use 16-bit Datalinks. To read (and/
or write) a 32-bit parameter using 16-bit Datalinks, typically both Datalinks
of a pair (A, B, C, D) are set to the same 32-bit parameter. For example, to
read Parameter 10 - [Elapsed Run Time] in a PowerFlex 70 drive, both
Datalink A1 Out and Datalink A2 Out are set to “10.” Datalink A1 Out will
contain the least significant word (LSW) and Datalink A2 Out will contain
the most significant word (MSW).
Topic Page
Using Datalinks 7-1
Using Datalinks with Modbus 7-3
Using Datalinks with Metasys N2 7-4
Using Datalinks with Siemens P1 FLN 7-5