Rockwell Automation 9323-PA1E USER MANUAL APS 6.0 - Manual (Page 246)

Preface
Advanced Programming Software User Manual
12–12
Important Recommendations When Using DH-485 Devices
The following summarizes the recommendations for a DH-485 network.
•
Use node 0 and the lowest node numbers for APS terminals.
•
Number the processor nodes consecutively, beginning at the lowest possible
number.
•
Set the maximum node address as low as possible. The highest numbered node
should have its maximum node address set to its own address.
•
Make certain that the baud rate settings of all nodes are the same. A terminal
will only communicate with processors set at the terminal’s baud rate.
•
Set the baud rate of the terminal at the Online Configuration display. The baud
rate for the processor nodes is set either at the Who Active display or in the
status data file of a processor file. Baud rate changes for SLC 5/01 and
SLC 5/02 processors take effect after cycling power to the processor. The
default baud rate for devices on the network is 19200.
•
A processor memory change using the restore or memory transfer function
overwrites the existing node address and existing baud rate after you cycle
processor power. If the processor node address is unknown, immediately after
you make such a processor memory change on an active DH-485 network,
select the Node Address function at the Who Active table; re-enter the node
address number at which you are presently located. Failure to do this can result
in a duplicate or incorrect node address after you cycle power to the processor.
If two processors on the DH-485 network are assigned the same node address,
it is possible that the processor file in one of the processors will be lost and
replaced with the default file.
If you press the DOS [Pause] key or [CTRL-Num Lock] while DH-485
network communication is taking place between APS and any SLC 500
processor, the network may fail.