Note: The information in this help topic applies when exchanging longs and/or floats among SIXNET stations configured to respond to Modbus protocol. Other Modbus compatible equipment may be addressed differently.
Daniel extension support is provided by some Modbus master and slave devices as a means of transferring floating point and long integer values as 32-bit registers. These extensions are detailed in the Daniel Industries document, Modbus Communications 2500 Host-Slave Communications Part Number 3-9000-545 Rev. C.
Some SIXNET stations can be configured with I/O Transfers to read / write longs and floats.
In the station’s I/O transfer definition, specify the "First Register Number" of the remote station as a Modbus address or as a SIXNET equivalent address. You can specify an odd or even first register address, as opposed to specifying only an odd-numbered Modbus address when transferring floats and longs as a pair of registers.
Here are some Modbus address examples. The first digit is the type number. The last 4 digits are the address. Note that a colon separator has been placed between the type number and the address for visual purposes only. Do not include a colon when entering a Modbus address.
DLI:0001 = Long input 0 of the station DLO:0001 = Long output 0 of the station
DLI:0002 = Long input 1 of the station DLO:0002 = Long output 1 of the station
DLI:0004 = Long input 3 of the station DLO:0004 = Long output 3 of the station
DFI:0001 = Floating input 0 of the station DFO:0001 = Floating output 0 of the station
DFI:0002 = Floating input 1 of the station DFO:0002 = Floating output 1 of the station
DFI:0004 = Floating input 3 of the station DFO:0004 = Floating output 3 of the station
See Also: Transferring Longs And Floats as a Pair of Analog Registers