ProSoft Technology MVI56E-MCMR - Manual (Page 167)

MVI56E-MCMR ♦ ControlLogix Platform Reference
Modbus Communication Module with Reduced Data Block User Manual
ProSoft Technology, Inc. Page 167 of 225
May 13, 2014
Cold Boot Block (9999)
The Cold Boot special function is used to restart the module application from
within processor logic. This allows the module to be restarted without removing it
from the chassis or removing power from the chassis. Restarting or "rebooting"
the module will momentarily interrupt normal module operation, such as Modbus
polling and backplane data transfers. It will also clear and reset all module
diagnostic counters and user database memory.
This special function is one of the few that is sent in the Output Image Write Data
block instead of a MSG instruction. Therefore, the effect of triggering a Cold Boot
is almost immediate.
If you follow the sample ladder logic or AOI, the block identification code 9999 for
the Cold Boot special function is embedded in the logic that formulates the Write
Data block to be sent to the module in the Output Image. You can activate this
special block logic by setting the controller tag, MCMR.CONTROL.C
OLD B OOT , to
a value of 1. This will force an immediate module reboot.
The following table describes the format of the Cold Boot data block constructed
by the processor.
Block Request from Processor to Module
Word Offset Description Length
0 9999 1
1 to 41 Spare 41
Warm Boot and Cold Boot special functions are almost identical in what they do
to reboot the module. The main difference between the two is that the Cold Boot
restarts the internal firmware application by interrupting backplane power to the
module. Therefore, a Cold Boot will take a few extra seconds to complete before
the module will return to normal operation than it would if a Warm Boot were
used. However, if the module is not operating correctly, and a Cold Boot may be
more effective at clearing errors and restarting the application than a Warm Boot
might be.