Prosoft-technology MVI69E-MBTCP Manuel d'utilisateur télécharger pdf (Page 65)

MVI69E-MBTCP ♦ CompactLogix Platform MVI69E-MBTCP Backplane Data Exchange

Modbus TCP/IP Enhanced Communication Module User Manual

ProSoft Technology, Inc. Page 65 of 150

May 20, 2015

4.3 Normal Data Transfer

Normal data transfer includes the paging of the user data found in the module’s

internal database (Registers 0 to 9999) and the status data. These data are

transferred through read (input image) and write (output image) blocks. The

following topics describe the structure and function of each block.

4.3.1 Write Block: Request from the Processor to the Module

These blocks of data transfer information from the processor to the module. The

structure of the output image used to transfer this data is shown below:

Offset

Description

Length (words)

Write Block ID

1 to (n)

Write Data

(n)

(n) = 60, 120, or 240 depending on the Block Transfer Size parameter (refer to the configuration

file).

The Write Block ID is an index value that determines the location in the module’s

database where the data is placed.

4.3.2 Read Block: Response from the Module to the Processor

These blocks of data transfer information from the module to the processor. The

structure of the input image used to transfer this data is shown below:

Offset

Description

Length (words)

Read Block ID

Write Block ID

2 to (n+1)

Read Data

(n)

(n) = 60, 120, or 240 depending on the Block Transfer Size parameter (refer to the configuration

file).

1 2 ... 60 61 62 63 64 65 66 67 68 69 70 ... 149 150

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Prosoft-technology MVI69E-MBTCP Manuel d'utilisateur Page 65