Yaskawa VS-616G5 Modbus Plus Communication Card - Manual (Page 32)

Basic MSTR Functions 6-3
Read Function
An MSTR read function (operation code = 2) will read data from one slave device on the network.
When using an MB+ network, an MSTR read function can be used to acquire the following types
of data:
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Command Data Registers
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Parameter Data Registers
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Monitor Data Registers
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Special Data Registers
An MSTR read function may take multiple scans of the PLC ladder to complete. Examples of
reading drive registers can be found in Chapter 9: Example #2 (read output frequency), Example
#3 (read global data), Example #7 (read drive parameters), and Example #9 (read drive status
registers).