Honeywell HC900 manual Replacing the Controller Module, Controller Module Replacement

Removal and Replacement Procedures - Safety Considerations - PLAN AHEAD!

Replacing the Controller Module

Removing and replacing the Controller Module requires that that the source of AC power is removed from the rack. Removing power from the Controller rack has the following consequences:

•All control action stops

•All power to all I/O modules in the rack is lost; hence all control outputs to the process are lost. Because external power connected to terminal boards (from or to field devices) will still be present, it is essential that field devices are maintained in a safe condition during replacement procedures.

•Control to all I/O expansion racks(C50 CPU only) is lost. If power is available to the expansion racks, outputs go to configured Failsafe values.

Before replacement:

•(If possible), upload and SAVE a copy of the configuration, or ensure that a previously SAVEd copy of the current configuration is available.

•(If possible), bring the process to a safe and orderly shutdown.

	Table 32 - Controller Module Replacement
Step	Action
1.	If a process is currently in operation, bring it to a safe and orderly shutdown.
2.	Using an external (user-supplied) switch, disconnect the power supply in the Controller rack
	from the site AC power source.
3.	Observe where communications cables are plugged into the Controller Module, and if necessary,
	tag them to identify their functions. Unplug all communications cables.
3.	At the top and bottom of the module, loosen the captured screws that secure the module in the
	rack, and remove the Controller Module from the rack.
4.	Ensure that the new Controller Module is properly aligned with the slot guides, insert the new
	Controller Module in the rack, and secure it in place with the captured screws at top and bottom
	of the module.
5.	Re-install communications cables.
6.	Using the (user-supplied) switch, re-connect site AC power to the rack.
	If using the Ethernet port for configuration, use the Hybrid Control Designer software to set the
	proper network address.
7.	Download the configuration.
8.	Set the Real-Time Clock.
9.	If all status indications are green, power may be restored to the I/O modules per the application's
	procedures.

148	HC900 Hybrid Controller Installation and User Guide	Revision 5
		9/03