ProSoft Technology 5202-DFNT-MCM4 - Manual (Page 19)

MCM Protocol Configuration MCM ♦ ProLinx Gateway
Driver Manual Modbus Master/Slave
ProSoft Technology, Inc.
Page 19 of 80
October 16, 2009
3.1.4 Float Flag
Yes or No
This flag specifies how the Slave driver will respond to Function Code 3, 6, and
16 commands (read and write Holding Registers) from a remote Master when it
is moving 32-bit floating-point data.
If the remote Master expects to receive or will send one, complete, 32-bit
floating-point value for each count of one (1), then set this parameter to Y
ES ,
especially if the Master must read or write from Modbus addresses above
gateway address 3999 (virtual Modbus address 44000 or 440000). When set to
Y
ES , the Slave driver will return values from two, consecutive, 16-bit internal
memory registers (32 total bits) for each count in the read command or receive
32-bits per count from the Master for write commands. Example: Count = 10,
Slave driver will send 20, 16-bit registers for 10 total 32-bit floating-point values.
If, however, the remote Master sends a count of two (2) for each 32-bit floating-
point value it expects to receive or send, or, if you do not plan to use floating-
point data in your application, then set this parameter to N
O , which is the default
setting.
You will also need to set the Float Start and Float Offset parameters to
appropriate values whenever the Float Flag parameter is set to Y
ES .
3.1.5 Float Start
0 TO 65535
Whenever the Float Flag parameter is set to Y ES , this parameter determines the
lowest Modbus Address received in commands from a remote Master to consider
as requests to read or write floating-point data. All commands with address
values greater than or equal to this value will be considered floating-point data
requests. All commands with address values less than this value will be
considered normal 16-bit register data requests.
This parameter is used only if the Float Flag is set to Y ES . For example, if a value
of 7000 is entered, all commands received with addresses of 47001 (or 407001)
and above will be considered as requests for floating-point data and 32-bits of
data will be returned for each count of one in the command.
You will also need to set the Float Offset parameter to an appropriate value
whenever the Float Flag parameter is set to Y
ES .