Rockwell Automation 1794-L34 FlexLogix Controller System User Manual - Manual (Page 41)

Publication 1794-UM001G-EN-P - January 2007
Communicate over Networks 41
• RSLogix 5000 programming software to configure the serial port
of the controller for DH-485 communications.
Specify these characteristics on the Serial Port tab (default values
are shown in bold):
For more information... The Data Highway/Data Highway Plus/Data Highway II/Data
Highway-485 Cable Installation Manual, 1770-6.2.2 describes how to
plan and install a DH-485 network.
Characteristic: Description:
Baud Rate Specifies the communication rate for the DH-485 port. All devices
on the same DH-485 network must be configured for the same
baud rate. Select 9600 or 19200 Kbps.
Node Address Specifies the node address of the controller on the DH-485
network. Select a number 1-31 decimal, inclusive.
To optimize network performance, assign node addresses in
sequential order. Initiators, such as personal computers, should
be assigned the lowest address numbers to minimize the time
required to initialize the network.
Token Hold Factor Number of transmissions (plus retries) that a node holding a
token can send onto the data link each time that it receives the
token. Enter a value between 1-4. The default is 1.
Maximum Node
Address Specifies the maximum node address of all the devices on the
DH-485 network. Select a number 1-31 decimal, inclusive.
To optimize network performance, make sure:
• the maximum node address is the highest node number being
used on the network
• that all the devices on the same DH-485 network have the
same selection for the maximum node address.