Addressing tips -6, Addressing tips – Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM User Manual
Page 24
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Publication AG-UM008C-EN-P - February 2005
1-6 Designing Communication
Addressing Tips
Each station on the network including the master station must have a
unique address. The address range is 0 to 254
10
(376
8
), so you can
have a maximum of 254
stations on a single telemetry network. Station
address 255
10
(377
8
) is the broadcast address, which you cannot select
as a station’s individual address.
A remote programming terminal station address should be reserved,
even if remote programming is not considered a requirement initially.
This address will need to be periodically polled, even though it will
remain on the inactive poll list unless a remote programming terminal
is online.
SLC 500 and MicroLogix 1000 Processor Addressing Considerations
When an SLC 5/02 or MicroLogix 1000 slave station issues a
PLC
®
-2-type message to a PLC-5 master station, the message’s
destination in the PLC-5 processor’s data table is an integer file with
the file number equal to the SLC 500 or MicroLogix 1000 processor
station address.
An address lower than 9 may interfere with a PLC-5 processor master
station since files 0-8 are usually left in their default configuration; file
9 is often used by programmers for the I/O list. Station address 255
10
is the broadcast address. So, assign addresses between 10
10
-254
10
.
When using an SLC 5/03, 5/04, or 5/05 processor, or a MicroLogix
1100, 1200 or 1500 controller, as a master station, the poll list
configuration consists of a contiguous block of addresses. Therefore,
assign slave station addresses in a contiguous block in order to avoid
polling for nonexistent slave stations.
TIP
For all other master station types, the SLC 5/02
or MicroLogix 1000 slave station can initiate a 500
CPU-type message.