MVI56E-MCMR ♦ ControlLogix Platform
Reference
Modbus Communication Module with Reduced Data Block
User Manual
ProSoft Technology, Inc.
Page 165 of 223
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.
