Allen-Bradley 1794ASB Series B User Manual

3–3 Communicating with FLEX I/O Modules
Publication 17946.5.3 - May 1996
Some examples of rack definition are shown below.
Adapter
Adapter
Each module is equal to 1 I/O group. Therefore, there are 4 I/O groups to be created. Four I/O groups equal
1/2 of a logical rack. The remote I/O adapter will see this configuration as 1/2 of a logical rack
Each module is equal to 1 I/O group. The first empty terminal base is counted as 1 I/O group since it is not at the
end of the rack. The second and third empty bases are not counted since they are at the end of the rack.
Therefore, there are 5 I/O groups to be created. Five I/O groups are greater than 1/2 rack but less than 3/4 rack.
The remote I/O adapter will see this configuration as the next highest rack, in this case, 3/4 of a logical rack with
the last I/O groups not mapped.
= 1/2 Rack
= 1/2 Rack
Module Empty Empty EmptyModule Module Module
Module Module Module Module
Adapter Module Empty Empty EmptyModuleEmpty
= 3/4 Rack
Each module is equal to 1 I/O group. The first and second empty terminal bases are counted as 1 I/O group each,
since they are not at the end of the rack. The third and fourth empty bases are not counted since they are at the
end of the rack. Therefore, there are 4 I/O groups to be created. Four I/O groups are equal to 1/2 rack. The
remote I/O adapter will see this configuration as 1/2 of a logical rack.
Example 1 - 4 Terminal Bases, 4 Modules
Example 2 - 6 Terminal Bases, 2 Modules
Example 3 - 7 Terminal Bases, 4 Modules
Adapter
Starting
Module
Group 4
45 67 0 123
Do not attempt to mix module groups from separate logical I/O rack numbers. All I/O module groups must
be in the same logical I/O rack.
Example 4 - Illegal Module Grouping - An illegal grouping consists of more than 1 logical I/O rack attached to 1 adapter.

Allen-Bradley 1794ASB Series B Specifications

General

Brand	Allen-Bradley
Model	1794ASB Series B
Category	Adapter
Language	English