Using immediate data-transfer operations – Rockwell Automation 1785-Lx0C15 ControlNet PLC-5 Programmable Controllers User Manual User Manual

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1785-UM022C-EN-P - February 2008

2-8

Planning to Use Your ControlNet PLC-5 Processor

Using Immediate Data-Transfer Operations

ControlNet Immediate Data I/O transfers—Immediate Data Input
(IDI) and Immediate Data Output (IDO)—perform similarly to the
Remote-I/O supported immediate I/O transfers—Immediate Input
(IIN) and Immediate Output (IOT)—which the ControlNet system
also supports. The logic scan is temporarily interrupted while the
most recent state of up to 64 words is read from or written to the
private memory buffer.

ControlNet Data Transfer

Private
Memory
Buffers

Housekeeping

Logic Scan

Program Scan

Data-
Table
Files

Immediate Data Transfer

= Unscheduled Data Transfer

= Scheduled Data Transfer

= NUI

Data Update