User manual

1785-UM022B-EN-P - February 2002

4-6 Programming Your ControlNet System

1771 ControlNet Transfers in PIIs and STIs

When a 1771 Read or 1771 Write CIO instruction is encountered in a

PII or STI, the processor resumes execution of lower priority ladder

programs (main logic programs) until the CIO is completed. If you

want the PII or STI to run to completion before returning to your

main logic program, place the CIO instruction inside of a UID/UIE

pair in your PII or STI program file.

Using ControlNet

Immediate Data Input and

Output Instructions

You can use two instructions for immediate data input and output on a

ControlNet network—Immediate Data Input (IDI) and Immediate

Data Output (IDO).

IMMEDIATE DATA INPUT

Data file offset

Length

Destination

IDI

IMMEDIATE DATA OUTPUT

Data file offset

Length

Source

ID0

232

N11:232

175

N12:175