Rockwell Automation 22C PowerFlex 400 AC Drive FRN 1.xx - 7.xx - Manual (Page 192)

E-2 Modbus RTU Protocol
PowerFlex 400 Adjustable Frequency AC Drive FRN 1.xx - 7.xx User Manual
Publication 22C-UM001I-EN-P
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.
Parameter Configuration
The following PowerFlex 400 parameters are used to configure the drive
to operate on a network.
Supported Modbus Function Codes
The peripheral interface (DSI) used on PowerFlex 400 drives supports
some of the Modbus function codes.
Important: Modbus devices can be 0-based (registers are numbered
starting at 0) or 1-based (registers are numbered starting at
1). Depending on the Modbus Master used, the register
addresses listed on the following pages may need to be
offset by +1. For example, Logic Command may be register
address 8192 for some master devices (e.g. ProSoft
3150-MCM SLC Modbus scanner) and 8193 for others
(e.g. PanelViews).
Parameter Details Reference
P036 [Start Source] Set to 5 “RS485 (DSI) Port” if Start is controlled from
the network. Page 3-8
P038 [Speed Reference] Set to 5 “RS485 (DSI) Port” if the Speed Reference is
controlled from the network. Page 3-10
C102 [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 3-31
C103 [Comm 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 3-31
C104 [Comm Node Addr] Sets the node address for the drive on the network.
Each device on the network requires a unique node
address. Page 3-32
C105 [Comm Loss Action] Selects the drive’s response to communication
problems.
Page 3-32
C106 [Comm Loss Time] Sets the time that the drive will remain in
communication loss before the drive implements C105
[Comm Loss Action]. Page 3-32
C107 [Comm Write Mode] Determines whether parameter changes made over
communication port are saved or stored in RAM only. If
they are stored in RAM, the values will be lost at
power-down.
Page 3-31
Modbus Function Code Command
03 Read Holding Registers
06 Preset (Write) Single Register
16 (10 Hexadecimal) Preset (Write) Multiple Registers