ProSoft Technology CompactLogix MVI69E-MBS User Manual page 131

MVI69E-MBS ♦ CompactLogix™ Platform
Modbus Serial Enhanced Communication Module
Example #3: Master is issuing Modbus command with FC 3 to transfer Float data from slave.
Float Flag: Not applicable with Modbus Function Code 3.
Float Start: Not applicable with Modbus Function Code 3.
DB Addr - Tells the master where in its data memory to store the data obtained from the
slave.
Reg Count - Tells the master how many registers to request from the slave.
Swap Code - same as above.
Func Code - Tells the master to read the register values from the slave. FC3.
Addr in Dev - Tells the master where in the slave's database to obtain the data.
In the above example, the master's Modbus command to transmit inside the Modbus
packet is as follows.
Slave Address
01
DEC
01
HEX
In the above example the (Enron/Daniel supporting) slave's Modbus command to
transmit inside the Modbus packet is as follows.
Slave Address
01
DEC
01
HEX
In the above example the (a NON-Enron/Daniel supporting) slave's Modbus command
that is transmitted inside the Modbus packet is as follows.
Slave Address
01
DEC
01
HEX
ProSoft Technology, Inc.
Function Code Address in Device
3 6100
03 17 D4
Function Code Byte Count
3 8
03 08
Function Code Byte Count
3 4
03 04
Reg Count
2
00 02
Data
32.75 275.69
00 00 42 03 D8 52 43 89
Data
32.75
00 00 42 03
Reference
User Manual
Page 131 of 159