30
Unit Numbers and I/O Word Allocation
Section 3-2
I/O Word Allocation Examples
The following examples show four possible Systems and the word allocations
for them. They do not show all possible connections or the maximum number
of Units possible for each System. Refer to Section 4-1 for the maximum
number of connectable Units.
With two Slaves connected to one Master, the Slaves are set to unit numbers
0 and 1. The order does not matter. The last Unit must be set as the termina-
tor. If only one Slave is connected, set it to unit number 0 and as the termina-
tor. Words are automatically allocated for all I/O Units.
16 pts.
32 pts.
64 pts.
16 pts.
IR 7
IR 5 & 6
IR 1, 2, 3, & 4
IR 0
32 pts.
32 pts.
16 pts.
16 pts.
IR 18 & 19
IR 16 & 17
IR 15
IR 14
32 pts.
16 pts.
16 pts.
16 pts.
16 pts.
IR 24 & 25
IR 23
IR 22
IR 21
IR 20
Slave
Set to
Unit #0.
Slave Set
to Unit #1.
Set as ter-
minator.
Slave
Set to Unit #0.
Set as terminator.
16 pts.
16 pts.
64 pts.
IR 13
IR 12
IR 8, 9, 10, & 11
16 pts.
32 pts.
IR 28
IR 26 & 27
Masters
CPU Rack
Expansion I/O
Rack
Slave Rack
Slave Rack
Slave Rack
Example 1: C500 with
Slaves
