User manual

Publication CNET-UM001C-EN-P - November 2005
D-4 Control 1771 I/O Over ControlNet
Read or Write Data To or
From a Block Transfer
Module Via a Message
Instruction
Use this procedure to transfer data to or from a module that requires block
transfers. Use an INT buffer in the message and move the data into or out of
the buffer as needed because DINTs can increase the program scan.
Read Data From a Block Transfer Module
1. To read data from a block transfer module, enter the following rung of
ladder logic:
This table describes the tags used in this message
/
msg_read.EN
/
msg_write.EN
EN
DN
ER
Type - Block Transfer Read
Message Control msg_read
...
MSG
Reads 16-bit integers (INTs) from the module and stores them in int_buffer_read. (Only include the msg_write.EN tag and associated instruction
if
you also send a block transfer write message to the same module.)
Table D.1 Tag Description
Tag Name: Description: Data Type: Scope:
msg_read block transfer
read message
MESSAGE name_of_controller
(controller)