Before You Begin - Allen-Bradley 1769-PA2K Installation Instructions Manual

WARNING: Special Conditions for Safe Use:
• This equipment is not resistant to sunlight or other sources of UV radiation.
• This equipment shall be mounted in an ATEX/IECEx Zone 2 certified enclosure with a minimum
ingress protection rating of at least IP54 (as defined in EN/IEC 60529) and used in an
environment of not more than Pollution Degree 2 (as defined in EN/IEC 60664-1) when applied
in Zone 2 environments. The enclosure must be accessible only by the use of a tool.
• This equipment shall be used within its specified ratings defined by Rockwell Automation.
• Provision shall be made to prevent the rated voltage from being exceeded by transient
disturbances of more than 140% of the rated voltage when applied in Zone 2 environments.
• This equipment must be used only with ATEX/IECEx certified Rockwell Automation backplanes.
• Do not disconnect equipment unless power has been removed or the area is known to be
nonhazardous.
• Secure any external connections that mate to this equipment by using screws, sliding latches,
threaded connectors, or other means provided with this product.
ATTENTION: This equipment is not resistant to sunlight or other sources of UV radiation.

Before You Begin

There are some points about power distribution that you must know.
• The master control relay must be able to inhibit all machine motion by removing power
to the machine I/O devices when the relay is de-energized. We recommend that the
controller remains powered even when the master control relay is de-energized.
• If you are using a DC power supply, interrupt the load side rather than the AC line
power. This operation avoids the additional delay of power supply turn-off. The DC
power supply must be powered directly from the fused secondary of the transformer.
Power to the DC input and output circuits must be connected through a set of master
control relay contacts.
Perform Periodic Tests of Master Control Relay Circuit
Any part can fail, including the switches in a master control relay circuit. The failure of one of
these switches would most likely cause an open circuit, which would be a safe power-off failure.
However, if one of these switches shorts out, it no longer provides any safety protection. These
switches must be tested periodically to make sure they stop machine motion when needed.
Rockwell Automation Publication 1769-IN028I-EN-P - July 2020
Compact I/O Expansion Power Supplies
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