Rockwell Automation 20D PowerFlex 700S with Phase I Control Reference Manual - Manual (Page 118)

118 Rockwell Automation Publication PFLEX-RM002D-EN-E - August 2013
Chapter 1 Detail Drive Configuration and Operation
Figure 29 - Writing Floating-Point Datalinks in an SLC/PLC-5
Explicit Block Transfer Messaging
Explicit block transfer messaging is used to configure the drive and monitor data
from the drive. This type of block transfer is different than the block transfer
used to transmit and receive datalinks. Chapter 5 of the 20-COMM-R User
Manual shows the format of the block transfer request and response data in an
SLC and PLC-5.
Because the SLC/PLC-5 does not support 32-bit integers, 32-bit integer data
from the block transfer request and response data remains split into (2) 16 bit
integers. In order to send or receive floating-point data we have to swap the LSW
and MSW and utilize the COP (copy) instruction. The following examples are
for transmitting and receiving floating-point data for block transfer messages, but
do not show the logic for the block transfer explicit messages themselves. See
Chapter 5 of the 20-COMM-R User Manual for an example program for the
block transfer explicit messages.
A floating point datalink is sent across RIO as 2, 16 bit intergers. To write a floating point datalink correctly in the SLC, you must first
copy the floating point into 2 intergers, then swap the high and low 16 bit intergers.
F12:6 = Datalink A1 In
N13:12 = MSW Datalink A1 In
N13:13 = LSW Datalink A1 In
N10:12 = LSW Datalink A1 In from RIO BT Write
N10:13 = MSW Datalink A1 In from RIO BT Write
0007
MOV
Move
Source
Dest
N13:13
0
F10:12
0
MOV
Move
Source
Dest
N13:12
16800
N10:13
16800
COP
Copy File
Source
#F12:6
Dest #F13:12
Length 2