ProSoft Technology MVI71-MNET - Manual (Page 22)

MVI71-MNET ♦ PLC Platform Module Configuration
Modbus TCP/IP Interface Module User Manual
Page 22 of 109
ProSoft Technology, Inc.
June 23, 2009
2.2 Module Data
All data related to the MVI71-MNET module is stored in a user defined data files.
It is the responsibility of the ladder logic programmer to construct all the data files
required by the program and to write the ladder logic required to interface to
these files.
2.3 Status Data
When the side-connect interface is employed in the application, the status data is
automatically transferred from the module to the first file used by the interface.
The data is placed at an offset of 0 in the file and has the format shown in the
Reference chapter.
When the block transfer interface is used, the status data is placed in the
module’s internal database at the location specified by the Error/Status Offset
parameter in the configuration file. If this data area is transferred to the processor
in the read data area, it will be passed from the module to the processor in a
normal BTR block. This will be placed in the normal read data area. The format
of the data is exactly the same as shown above, but the user determines its
position. Refer to the Reference chapter for a complete listing of the data stored
in this object.
2.4 User Data
When the side-connect interface is utilized, the read and write data is moved
between the module and the processor without any ladder logic. The size of the
data area and position of the data areas in the module’s database is determined
by the parameters set in the configuration file.
When the block transfer interface is used, ladder logic is required to page the
data between the module and the processor. The size of the data area and
position of the data areas in the module’s database is determined by the
parameters set in the configuration file.
The read data area should be set to match the value entered in the Read
Register Count parameter of the MNET.CFG file. For ease of use, this array
should be dimensioned as an even increment of 60 words. This data is paged up
to 60 words at a time from the module to the processor. The Read Data task is
responsible for placing the data received into the proper position in the read data
array. Use this data for status and control in the ladder logic of the processor.
The write data area should be set to match the value entered in the Write
Register Count parameter of the MNET.CFG file. For ease of use, this array
should be dimensioned as even increments of 60 words. This data is paged up to
60 words at a time from the processor to the module. The Write Data task is
responsible for placing the write data into the output image for transfer to the
module. This data is passed from the processor to the module for status and
control information for use in other nodes on the network.