174 Rockwell Automation Publication 520-UM001A-EN-E - February 2013
Appendix C RS485 (DSI) Protocol
Only pins 4 and 5 on the RJ45 plug should be wired. The other pins on the
PowerFlex 525 RJ45 socket must not be connected because they contain power,
etc. for other Rockwell Automation peripheral devices.
Wiring terminations on the master controller will vary depending on the master
controller used and “TxRxD+” and “TxRxD-” are shown for illustration
purposes only. Refer to the master controller’s user manual for network
terminations. Note that there is no standard for the “+” and “-” wires, and
consequently Modbus device manufacturers interpret them differently. If you
have problems with initially establishing communications, try swapping the two
network wires at the master controller.
Standard RS485 wiring practices apply.
• Termination resistors need to be applied at each end of the network cable.
• RS485 repeaters may need to be used for long cable runs, or if greater than
32 nodes are needed on the network.
• Network wiring should be separated from power wires by at least
0.3 meters (1 foot).
• Network wiring should only cross power wires at a right angle.
I/O Terminal C1 (RJ45 Shield) on the PowerFlex 525 drive must also be
connected to PE ground (there are two PE terminals on the drive). See Control
I/O Terminal Designations on page 33 for more information.
I/O Terminal C2 (Comm Common) is internally tied to Network Common,
and NOT to RJ45 Shield. Tying I/O Terminal C2 to PE ground may improve
noise immunity in some applications.
Parameter Configuration
The following PowerFlex 525 parameters are used to configure the drive to
operate on a DSI network.
Configuring Parameters for DSI Network
Parameter Details Reference
P046
[Start Source 1] Set to 3 “Serial/DSI” if Start is controlled from the network. page 71
P047 [Speed Reference1] Set to 3 “Serial/DSI” if the Speed Reference is controlled from the network. page 72
C123 [RS485 Data Rate] Sets the data rate for the RS485 (DSI) Port. All nodes on the network must be
set to the same data rate.
page 85
C124 [RS485 Node Addr] Sets the node address for the drive on the network. Each device on the
network requires a unique node address.
page 85
C125 [Comm Loss Action] Selects the drive’s response to communication problems. page 85
C126 [Comm Loss Time] Sets the time that the drive will remain in communication loss before the
drive implements C125 [Comm Loss Action].
page 85
C127 [Comm Format] Sets the transmission mode, data bits, parity and stop bits for the RS485 (DSI)
Port. All nodes on the network must be set to the same setting.
page 86
C121 [Comm Write Mode] Set to 0 “Save” when programming drive.
Set to 1 “RAM only” to only write to volatile memory.
page 85
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