ProSoft Technology MVI56-101S - Manual (Page 100)

Reference MVI56-101S ♦ ControlLogix Platform
User Manual IEC 60870-5-101 Slave Communication Module
Page 100 of 193 ProSoft Technology, Inc.
August 2, 2011
All data transferred between the module and the processor over the backplane is
through the input and output images. Ladder logic must be written in the
ControlLogix processor to interface the input and output image data with data
defined in the Controller Tags. All data used by the module is stored in its internal
database. The following illustration shows the layout of the database:
Module’s Internal Database Structure
5000 registers for user data 0
Register Data
4999
Data contained in this database is paged through the input and output images by
coordination of the ControlLogix processor ladder logic and the MVI56-101S
module's program. Up to 248 words of data can be transferred from the module
to the processor at a time. Up to 247 words of data can be transferred from the
processor to the module. The read and write block identification codes in each
data block determine the function to be performed or the content of the data
block. The module uses the following block numbers:
Block Range Descriptions
-1 Null Block
0 Null Block
1 to 25 Read or Write Data
1000 to 1024 Request Output Data from Processor
9958 Event Messages from CLX
9970 Set PLC time using module's time
9971 Set module's time using CLX time
9998 Warm-boot control block
9999 Cold-boot control block
Each image has a defined structure depending on the data content and the
function of the data transfer.
5.2.2 Normal Data Transfer
Normal data transfer includes the paging of the user data found in the module’s
internal database in registers 0 to 4999 and the status data. These data are
transferred through read (input image) and write (output image) blocks. Refer to
the Module Configuration and Ladder Logic sections for a description of the
data objects used with the blocks and the ladder logic required. The structure
and function of each block is discussed in the following topics.