Rockwell Automation 1756-L6x_L7x ControlLogix System User Manual - Manual (Page 29)

Rockwell Automation Publication 1756-UM001O-EN-P - October 2014 29
Install the 1756-L7x Controller Chapter 1
.
Uninstall the ESM
Consider these points before removing the ESM:
• The following ESM modules can be currently installed in your 1756-L7 x
or 1756-L7 xXT controller:
– 1756-ESMCAP
– 1756-ESMNSE
– 1756-ESMCAPXT
– 1756-ESMNSEXT
IMPORTANT Allow the ESM to finish charging before removing power from the controller.
Failure to do so can result in the loss of the application program. A type 1,
code 40 major fault is logged on powerup.
To verify that the ESM is fully charged, check the status display to confirm that
messages CHRG or ESM charging are no longer indicated.
TIP We recommend that you check the WallClockTime object attributes after
installing an ESM to verify that time of the controller is correct.
The ESM contains a real-time clock. If the ESM is new or came from another
controller, the WallClockTime object attributes for your controller can change.
WARNING: If your application requires the ESM to deplete its residual stored
energy to 40 μJoule or less before you transport it into or out of the application,
use only the 1756-(SP)ESMNSE(XT) module. In this case, complete these steps
before you remove the ESM.
• Turn power off to the chassis.
After you turn power off to the chassis, the controller’s OK status indicator
transitions from green to solid red to OFF.
• Wait at least 20 minutes for the residual stored energy to decrease to
40 μJoule or less before you remove the ESM.
There is no visual indication of when the 20 minutes has expired. You must track
that time period.
WARNING: When you insert or remove the energy storage module while
backplane power is on, an electrical arc can occur. This could cause an explosion
in hazardous location installations.
Be sure that power is removed or the area is nonhazardous before proceeding.
Repeated electrical arcing causes excessive wear to contacts on both the module
and its mating connector.
IMPORTANT Before you remove an ESM, make necessary adjustments to your program
to account for potential changes to the WallClockTime attribute.