ProSoft Technology MVI56-DFCMR - Manual (Page 66)

MVI56-DFCMR ♦ ControlLogix Platform Reference
DF1 Interface Module with Reduced Data Block
Page 66 of 113 ProSoft Technology, Inc.
October 20, 2008
3 Initialize Module Register space
4 Enable Slave Driver on selected ports
5 Enable Master Driver on selected ports
After the module has received the Module Configuration Block from the
processor, the module will begin communicating with other nodes on the
network, depending on the configuration.
Main Logic Loop
Upon completing the power up configuration process, the module enters an
infinite loop that performs the following functions:
ControlLogix Processor Not in Run
Whenever the module detects that the processor has gone out of the Run mode
(that is, Fault or PGM), the DF1 ports can be shut down as prescribed in the user
configuration. When the processor is returned to a running state, the module will
resume communications on the network.
Backplane Data Transfer
The MVI56-DFCMR 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 and MSG
instructions. 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 for the input and output images. Typical updates are in the range of 1 to
10 milliseconds. Execution time for the MSG instructions for data transfer are
dependant on the amount of unscheduled time in the Network Update Time
(NUT) and how frequently the instruction is executed.