ProSoft Technology MVI56E-SIE - Manual (Page 138)

Reference MVI56E-SIE ♦ ControlLogix Platform
User Manual Client Communication Module
Page 138 of 168 ProSoft Technology, Inc.
September 6, 2012
These block identification codes can be broken down into two groups:
Normal data transfer blocks
 Read and Write blocks (-1 to 25)
Special function blocks
 Initialize Output Data blocks (1000 to 1024)
 Client Status blocks (3000 to 3029)
 Command Control blocks (5001 to 5016)
 Module IP Address blocks (9990 and 9991)
 Warm-boot and Cold-boot blocks (9998 and 9999)
5.2.1 Normal Data Transfer Blocks
Normal data transfer includ es the paging of user data from the module’s internal
database (registers 0 to 4999), as well as paging of status data. These data are
transferred through read (input image) and write (output image) blocks.
The following topics describe the function and structure of each block.
Read Block
These blocks of data transfer information from the module to the ControlLogix
processor.
The following table describes the structure of the input image.
Read Block from Module to Processor
Word Offset Description Length
0 Reserved 1
1 Write Block ID 1
2 to 201 Read Data 200
202 Program Scan Counter 1
203 to 208 Block Transfer Status 6
209 to 238 Command bit data for Clients 20
239 to 240 Product Code 2
241 Product Version 1
242 to 248 Reserved 7
249 Read Block ID 1
The Read Block ID is an index value used to determine where the 200 words of
data from module memory will be placed in the ReadData[x] controller tag array
of the ControlLogix processor. Each transfer can move up to 200 words (block
offsets 2 to 201) of data. In addition to moving user data, the block also contains
status data for the module. The Write Block ID associated with the block requests
data from the ControlLogix processor.
During normal program operation, the module sequentially sends read blocks
and requests write blocks.