Bradley Smoker PLC-5 Remote I/O Scan Extended Local, Racks, Interrupt from STI or Fault Routine

Models: PLC-5

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Communicating with Remote I/O

6-13

 

 

Transferring Block Data

In addition to discrete data, the controller can also exchange block data with remote I/O. Block-transfer instructs the controller to interrupt normal I/O scanning and transfer as many as 64 words of data to/from a selected I/O module. The figure below shows how the scanner-mode controller handles a block-transfer.

Block-Transferring Data to Controller-Resident Local, Extended-Local, and Remote I/O

Remote I/O

Scan 2

 

 

 

Extended-

 

 

 

 

 

Local

 

 

 

 

 

I/O Scan 3

 

 

 

 

 

Local

Adapter

Remote I/O

 

Rack 4

 

 

 

 

 

 

 

 

 

 

 

 

Rack 7

 

Adapter

 

 

 

 

 

 

 

 

 

 

 

Local

 

 

 

 

 

 

 

 

 

 

Adapter

 

 

 

Racks 2

 

 

 

 

 

 

 

 

and 3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rack 6

 

Adapter

 

 

 

 

 

 

 

 

 

 

 

Local

 

 

 

 

 

Adapter

 

 

 

Rack 1

 

 

 

 

 

 

 

 

 

 

Rack 5

 

Adapter

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Controller-

 

 

Resident

 

 

Rack 0

1

 

 

Interrupt from STI or Fault Routine

2

The adapter used in the remote I/O scan is the 1771-ASB.

3

The adapter used in the extended-local I/O scan is the 1771-ALX.

Q = Queue

A = Active

Buffer BT

Requests

Q

BTR or BTW Data

One transfer per

A

 

I/O scan

1

 

 

BT Requests

One transfer per

Q

BTR or BTW Data

I/O scan

 

A

 

 

1

One transfer per

 

BT Requests

I/O scan

 

 

 

Q

BTR or BTW Data

 

A

1

One transfer per

 

BT Requests

I/O scan

Q

 

 

BTR or BTW Data

 

 

 

A

1

 

 

 

 

Logic

 

 

Scan

 

 

BT

 

 

Requests

 

Q

BTR or BTW Data

 

 

Multiple

A

1

 

Block Transfers

 

 

per I/O Scan

 

 

 

I/O Scan

Program

 

 

Scan

15299

Publication 1785-UM012D-EN-P - July 2005

Page 85
Image 85
Bradley Smoker PLC-5 Remote I/O Scan Extended Local, Racks, Interrupt from STI or Fault Routine, Multiple, Per I/O Scan