Communicating with Extended-Local I/O

8-3

 

 

PLC-5/40L Controller with 16-rack Addressing Capability (Split Between

Extended-Local I/O and Remote I/O)

Processor-resident local I/O racks

Extended-local I/O racks

0

1

2

3

 

4

5

 

6

7

10

11

 

 

 

 

 

Remote I/O racks

 

 

 

 

 

 

 

 

12

13

 

14

15

 

16

17

 

Note: Racks numbers do not need to be consecutive per channel. For example, remote I/O

 

racks can be numbered 6, 7, 14, 15, 16, and 17, while extended-local I/O racks can be

 

numbered 4, 5, 10, 11, 12, and 13.

18584

The PLC-5 controller and the 1771-ALX adapter module automatically allocate the next higher rack number(s) to the remaining I/O group(s) of the chassis. For example, if you select 1/2-slot addressing for your controller-resident local chassis and you are using a 16-slot (1771-A4B) chassis, the controller will address racks 0, 1, 2, and 3 in this chassis.

When assigning a rack number to extended local I/O, follow these guidelines:

Do not split a rack number between extended-local I/O and remote I/O. For example, if you use a partial rack for remote I/O, you cannot use the remaining partial rack for extended-local I/O. See ².

You can distribute extended-local I/O racks across multiple chassis on the extended-local I/O bus as shown below.

Extended-local I/O Rack Number Assigned to Multiple I/O Chassis

4

0

1

2

3

You can select a different hardware addressing method for each extended-local I/O chassis in your PLC-5 system.

Publication 1785-UM012D-EN-P - July 2005

Page 121
Image 121
Bradley Smoker PLC-5 user manual Processor-resident local I/O racks, Numbered 4, 5, 10, 11, 12