Rockwell Automation RECOMM-PBUS PROFIBUS Communications Module - Manual (Page 57)

Using I/O Messaging 6-5
• 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.
6.5.2 32-Bit Parameters using 16-Bit Datalinks
To read (and/or write) a 32-bit parameter using 16-bit Datalinks,
typically both Datalinks (A,B,C,D) are set to the 32-bit parameter.
For example, to read Elapsed MWh (SP600 drive parameter 9),
both Datalink A1 and A2 are set to “9.” Datalink A1 will contain the
least significant word (LSW) and Datalink A2 the most significant
word (MSW). In this example, the parameter 9 value of 5.8 MWh is
read as a “58” in Datalink A1.
Regardless of the Datalink combination, x1 will always contain the
LSW and x2 will always contain the MSW. In the following examples
Power Up Marker (drive parameter 242) contains a value of
88.4541 hours.
32-bit data is stored in binary as follows:
Datalink
Most/Least
Significant Word Parameter Data (decimal)
A1 LSW 9 58
A2 MSW 9 0
Datalink
Most/Least
Significant Word Parameter Data (decimal)
A1 LSW 242 32573
A2 - Not Used - 0 0
Datalink
Most/Least
Significant Word Parameter Data (decimal)
A1 - Not Used - 0 0
A2 MSW 242 13
Datalink
Most/Least
Significant Word Parameter Data (decimal)
A2 MSW 242 13
B1 LSW 242 32573
MSW 2 31 through 2 16
LSW 2 15 through 2 0