Addressing Modes for Your Remote I/O
Chapter 3
3-22
Some processors support a complementary I/O configuration. Refer to the
user’s manual for your processor to see if it supports this type of
configuration.
You configure complementary I/O by duplicating an I/O rack number of
one I/O chassis (primary) in another I/O chassis (complementary), I/O
group for I/O group. The I/O modules in the complementary chassis
perform the opposite function of the corresponding modules in the primary
chassis.
Module Placement with 1/2slot Addressing
Figure 3.19 shows possible module placement for a complementary I/O
configuration with 1/2-slot addressing.
Figure 3.19
Complementary
I/O Configuration with 1/2slot Addressing
IIO IOO
O
Double-slot
BT
E
M
P
T
Y
Example A
Example B
Primary 12-slot
Chassis
I/O G roup
Number
Complementary
12-slot Chassis
Primary 12-slot
Chassis
I/O G roup
Number
Complementary
12-slot Chassis
I=InputModule
O = Output Module
BT = Block transfer Module
1 Output modules use the same output image table bits
2 Can be input or output module (8-or 16-point) single-slot block tran fer module
3 Must be empty if corresponding primary slot is block transfer module
12
BT
OI
E
M
P
T
Y
OO I I O OI
I, O,
BT
IO
I
O
I
O
I
O
I
O
I
O
I
O
I
O
I
O
I
O
I
O
I
O
I
O
14261
1
01
01 23
23
45
45
67
67
01
01
23
23
45
45
67
67
01
01
23
23
45
45
67
67
33
s
Complementary I/O with
1/2Slot Addressing