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Chapter 4
Basic Programming Techniques
4-15
Connection Zero
There is a special connection that is opened automatically during the
coprocessor’s power–up procedure (figure 4.7). This is connection zero,
denoted as :C0.
Figure 4.7
Establishing a Connection to the OSI Coprocessor with :C0
OSI Network
Allen-Bradley OSI Coprocessor
As part of the power-up procedure,
a special connection is automatically
established from the coprocessor, to the coprocessor.
I - 12426
This connection is always available to the coprocessor operator and allows
you to manage your local MMS named variables without having to open or
close connections. With connection zero you also avoid using any of the
16 connections available for establishing connections to remote devices.
You cannot close or abort connection zero.
You can do the following to your local OSI coprocessor on connection
zero:
define MMS named variables (using the DEFVAR command)
delete MMS named variables (using the DELVAR command)
transfer data (using the SET or MOVE command)
Refer to each of the DEFVAR, DELVAR, and SET command sections later
in this chapter for special instructions on using connection zero. For
information on the MOVE command, refer to Chapter 5.
AB Parts