ProSoft Technology MVI94-MCM-MHI - Manual (Page 36)

Configuration MVI94-MCM ♦ Flex I/O Platform
User Manual Serial Communications Modbus Communication Module
Page 36 of 109 ProSoft Technology, Inc.
March 29, 2011
3.6.2 Internal Address
This field specifies the virtual Modbus database register to be associated with the
command. If the command is a read function, the data read from the slave device
will be placed starting at the register value entered in this field. If the command is
a write function, the data written to the slave device will be sourced from the
address specified. Register addresses specified for commands must reside in the
range specified by the Maximum Register parameter under the [MODBUS
MASTER] section.
3.6.3 Poll Interval Time
This parameter specifies the minimum interval to execute continuous commands
(Enable code of 1). The parameter is entered in units of seconds. Therefore, if a
value of 10 is entered for a command, the command will execute no more
frequently than every 10 seconds.
3.6.4 Count
This parameter specifies the number of registers or digital points to be
associated with the command. Functions 5 and 6 ignore this field as they only
apply to a single data point. For functions 1, 2 and 15, this parameter sets the
number of digital points (inputs or coils) to be associated with the command. For
functions 3, 4 and 16, this parameter sets the number of registers to be
associated with the command.
3.6.5 Swap Code
This parameter defines if the data received from the Modbus slave is to be
ordered differently than received from the slave device. This parameter is helpful
when dealing with floating-point or other multi-register values, as there is no
standard method of storage of these data types in slave devices. This parameter
can be set to order the register data received in an order useful by other
applications. The following table defines the values and their associated
operations.
Swap Code Description
0 None - No Change is made in the byte ordering (1234 = 1234)
1 Words - The words are swapped (1234=3412)
2 Words & Bytes - The words are swapped then the bytes in each word are
swapped (1234=4321)
3 Bytes - The bytes in each word are swapped (1234=2143)