DL06 Micro PLC User Manual; 3rd Edition Rev. E
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Chapter 4: System Design and Configuration
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MODBUS Read from Network(MRX)
The MODBUS Read from Network (MRX) instruction is used by the DL06 network master
to read a block of data from a connected slave device and to write the data into V–memory
addresses within the master. The instruction allows the user the to specify the MODBUS
Function Code, slave station address, starting master and slave memory addresses, number of
elements to transfer, MODBUS data format and the Exception Response Buffer.
• Port
Number:
must be DL06 Port 2 (K2)
• Slave Address:
specify a slave station address (0–247)
• Function Code
: The following MODBUS function codes are supported by the MRX
instruction:
01 – Read a group of coils
02 – Read a group of inputs
03 – Read holding registers
04 – Read input registers
07 – Read Exception status
08 – Diagnostics
• Start Slave Memory Address
: specifies the starting slave memory address of the data to be
read. See the table on the following page.
• Start Master Memory Address
: specifies the starting memory address in the master where
the data will be placed. See the table on the following page.
• Number of Elements
: specifies how many coils, input, holding registers or input register
will be read. See the table on the following page.
• MODBUS Data Format
: specifies MODBUS 584/984 or 484 data format to be used
• Exception Response Buffer
: specifies the master memory address where the Exception
Response will be placed. See the table on the following page.
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