Rockwell Automation 1785-Lx0C15 ControlNet PLC-5 Programmable Controllers User Manual - Manual (Page 88)

1785-UM022C-EN-P - February 2008
4-8
An IDO is initiated that updates the private memory output buffer
from the source file before the next normal output-image update. The
Data File Offset (175) is the offset into the buffer where the data is
stored. The Length (24) identifies the number of words in the transfer
or a logical address that specifies the number of words to be
transferred. The Source (N12:175) is the source of the words to be
transferred. The Source should be the matching data table address in
the DOF except when you use the instruction to ensure data-block
integrity in the case of Selectable Timed Interrupts (STIs). See Using
Selectable Timed Interrupts with a Program
on a ControlNet Network on page 4-9
For more detailed information about writing ladder programs and
programming ControlNet I/O transfers using Immediate Input (IIN)
and Immediate Output (IOT) instructions, see your programming
software documentation.
IDO
IMMEDIATE DATA OUTPUT
Data file offset
Length
Source
IDO instruction
copies from the
data table to the
private
DOF buffer Outputs transmitted
to the ControlNet
network on next
opportunity
N12:175 175
N12:0 0
Data Table Private DOF Buffer
175
24
N12:175