196 HC900 Process & Safety Controller User and Installation Manual Revision 6
21 April 2017
Removal and Replacement Procedures
Overview
This section contains procedures for removing and replacing the active components of an HC900 Process
Controller. It also includes recommendations, suggestions, and hints as they apply to the circumstances
under which the procedures are used.
Safety Considerations - PLAN AHEAD!
When using the procedures in this section, plan the sequence of procedural actions so as to ensure:
The safety of personnel
The protection of property
The integrity of operating processes
The first consideration is safety of personnel. While there is always an inclination to preserve the
materials and time invested in a running process, no action should ever be taken that would risk
injury to personnel.
Protection of personnel property is an important consideration that always requires comprehensive
knowledge of the entire control process: the control equipment, the process control strategy, and the
conditions and circumstances that exist when the removal and replacement procedures are taken.
The procedures in this section include notices of potential hazard as they apply to various components in
the controller. Because each control process and the set of conditions and circumstances at each user site
are unique, it is the user's responsibility to know the potential consequences of each action as it relates to a
running process.
It is recommended that the user becomes familiar with the significant aspects of each set of circumstances
and has a plan for execution of the proper action sequence.
All of the modules (input, output, RSM, PSM) available for use in the HC900 Controller have a RIUP
designation. That is, they can be Removed and Inserted Under Power, where "power" refers to DC
power at the backplane of the rack. (It does not refer to power for field wiring at the terminal board
associated with the I/O module, which must be disconnected (using a user-supplied switch) at the field
device before removing or inserting the module.
For all other components of the controller, AC power to the controller must be removed before removal
or replacement of the component.
Hazardous voltages exist at the Power Supply and at the terminal boards on I/O Modules
Only trained and authorized personnel should perform the procedures in this section.
Disconnect all sources of power associated with these components before removal or insertion.
Failure to comply with these instructions could result in death or serious injury.
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