Chapter 6 Transfering Data with the MSTR Instruction
MSTR Description
Introduction
All NOE 771 x0 Quantum Ethernet TCP/IP modules provide the user with the capability of transferring data to and from nodes on a TCP/IP network through the use of a special MSTR (master instruction). All PLCs that support networking communication capabilities over Modbus Plus and Ethernet can use the MSTR ladder logic instruction to read or write controller information.
MSTR
Operations
The MSTR instruction allows you to initiate one of 12 possible network communications operations over the network. Each operation is designated by a code. The following table lists the 12 operations and indicates those that are supported on an Ethernet TCP/IP network.
MSTR Operation TCP/IP Ethernet Support
Write data
Read Data
Get local statistics
Clear local statistics
Write global database
Read global database
Get remote statistics
Clear remote statistics
Peer Cop health
Reset Option Module
Read CTE(config extension)
Write CTE (config extension)
7
8
9
10
11
12
5
6
3
4
1
2
Operation
Type
supported supported supported supported not supported not supported supported supported supported supported supported supported
No. of MSTR
Instructions
Allowed
Up to16 MSTR instructions can be simultaneously serviced in a ladder logic program per NOE. More than 16 MSTRs may be programmed to be enabled by the logic flow as one active MSTR block releases the resources it has been using and becomes deactivated, the next MSTR operation encountered in logic can be activated.
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