
8.5
Modbus
Modbus is an internationally approved, asynchronous, serial communication protocol,
designed for commercial and industrial automation applications.
Information about the dimensioning of a Modbus network can be found in the
configuration document for the inverter.
Preconditions
•
Control unit (CU) of the inverter is provided with Modbus/CANopen.
•
Modbus/CANopen selector at the inverter front is set to "Modbus".
8.5.1
Modbus introduction
•
The process of data transmission distinguishes between three different operating modes:
Modbus ASCII, Modbus RTU, and Modbus TCP. The inverter supports the Modbus RTU oper-
ating mode ("Remote Terminal Unit").
•
The Modbus protocol is based on a master/slave architecture where the inverter always
works as slave.
•
The Modbus network only permits one master (at a time) sending commands and requests.
The master is also the sole instance to be allowed to initiate Modbus communication. No
direct communication takes place between the slaves.
•
The physical interface corresponds to TIA/EIA-485-A which is very common and suitable for
the industrial environment. This interface enables baud rates from 2400 to 115200 kbps.
•
The inverter supports Modbus function codes 3, 6, 16 (0x10) and 23 (0x17).
8.5.2
Modbus node address
Each network node must be provided with a unique node address.
Details
•
The node address can be set in
0x2321:001 (PAR 510/001)
.
•
The setting that is active when the inverter is switched on is the effective setting.
•
The node address 0 is reserved for messages to all nodes ("Broadcast") .
•
The active node address is shown in
0x2322:001 (PAR 511/001)
.
Parameter
Name / value range / [default setting]
Info
0x2321:001
(PAR 510/001)
Modbus settings: Node ID
(Modbus sett.: Node ID)
1 ... [1] ... 247
Setting of the node address.
•
A change in the node address only becomes effective after a restart of
Modbus communication.
0x2323
(PAR 509)
DIP switch position
(DIP switch)
•
Read only
Display of the DIP switch setting at the last mains power-on.
Configuring the network
Modbus
Modbus introduction
127
Phone: 800.894.0412 - Fax: 888.723.4773 - Web: www.actechdrives.com - Email: [email protected]