User guide

840 USE 115 00 Version 1.0
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3
The MSTR Instruction
3.1 Introduction
All NOE 2X1 10 Quantum Ethernet web embedded server modules provide the
user with the capabilit
y
of transferrin
g
data to and from nodes on a Modbus Plus or
TCP/IP network throu
g
h the use of a special MSTR
(
master instruction
)
. All PLCs
that support networkin
g
communication capabilities over Modbus Plus and
Ethernet can use the MSTR ladder lo
g
ic instruction to read or write controller
information.
3.2 MSTR Description
The MSTR instruction allows
y
ou to initiate one of 12 possible network
communications operations over the network. Each operation is desi
g
nated b
y
a
code. The followin
g
table lists the 12 operations and indicates those that are
supported on an Ethernet TCP/IP network.
MSTR Operation Code TCP/IP Ethernet Support
Write data 1 supported
Read Data 2 supported
Get local statistics 3 supported
Clear local statistics 4 supported