ProSoft Technology MVI71-MCM - Manual (Page 26)

MVI71-MCM ♦ PLC Platform Installing and Configuring the Module
Modbus Communication Module
Page 26 of 111 ProSoft Technology, Inc.
December 28, 2007
Modbus Port Parameters
These parameters define the operation of each of the Modbus ports on the
module. Refer to MVI71-MCM Configuration Data Definition (page 87) for a
definition of each parameter. These parameters are contained in the
configuration at offsets 6 to 55. Care must be taken when filling in this data area
for successful operation of the module in a user application.
Modbus Master Commands
These records define the commands in the master command list.
Each command has the following structure:
Offset Parameter
0 Enable
1 Internal
Address
2 Poll Interval
3 Count
4 Swap
5 Slave
Address
6 Function
7 Destination
Address
8 Spare
9 Spare
Enable - This parameter defines if the command will be executed or disregarded.
The following values are valid:
0=Disables the command
1=The command is considered for execution at each scan of the command list
and will be controlled by the PollInt parameter
2=The command will only execute if the data associated with the command has
changed since the command was last issued. This option is only available for
write commands.
Internal Address - This parameter specifies the starting internal register address
to be associated with the command. Valid entries for this parameter are 0 to
9999.
For example, if using a read holding register function (function 3), the Internal
Address parameter will have the address in the MVI71-MCM database in which
the value read from a Modbus slave is located. If using a write function (function
16), the Internal Address will have the source address in the MVI71-MCM
database which contains the value to be written to a Modbus slave device.