The MSTR Instruction
3.1Introduction
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All NOE 2X1 10 Quantum Ethernet web embedded server modules provide the user with the capability of transferring data to and from nodes on a Modbus Plus or 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.
3.2MSTR Description
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 | Code | TCP/IP Ethernet Support |
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| Write data | 1 | supported |
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| Read Data | 2 | supported |
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| Get local statistics | 3 | supported |
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| Clear local statistics | 4 | supported |
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840 USE 115 00 Version 1.0 | 25 |
