Reference
MVI56E-MNETCR ♦ ControlLogix Platform
User Manual
Modbus TCP/IP Multi-Client Enhanced Communications Module for Remote Chassis
Page 106 of 161
ProSoft Technology, Inc.
5.2
Backplane Data Transfer
The MVI56E-MNETCR module communicates directly over the ControlLogix
backplane. Data is paged between the module and the ControlLogix processor
across the backplane using the module's input and output images. The update
frequency of the images is determined by the scheduled scan rate defined by the
user for the module and the communication load on the module. Typical update
times range from 1 to 10 milliseconds.
This bi-directional transference of data is accomplished by the module putting
data in the module's input image to send to the processor. Data in the input
image is placed in the processor's controller tags by ladder logic. The input
image is set to 42 words.
Processor logic inserts data to the output image to be transferred to the module.
The module's firmware program extracts the data and places it in the module's
internal database. The output image is set to 42 words.
The following illustration shows the data transfer method used to move data
between the ControlLogix processor, the MVI56E-MNETCR module and the
Modbus TCP/IP Network.
Summary of Contents for MVI56E-MNETCR
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