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The same 140 XBE 100 00 Rack Expander modules are used for the primary and secondary racks. The end of the Rack Expander cable marked "Primary" always connects to the Rack Expander module in the primary rack.
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The system can use any Quantum type power supply. Each rack can have a different type of power supply.
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Loss of power in the secondary rack will not shut down the entire drop. Only modules located in the "Secondary" rack will lose power.
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Rack expander modules can be located in any slot in the rack and do not have to be placed in corresponding slots in the primary and secondary racks.
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I/O modules that have downloadable executive firmware, such as the ESI module, are allowed in the secondary rack—except when downloading their execs. Executive firmware cannot be downloaded to modules in the secondary rack.
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It may be necessary to update the CPU or RIO drop executive firmware. See the Executive Firmware section in Specifications.
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The Rack Expander will not be recognized by the programming panel software. It will look like an unfilled slot in the PLC I/O map.
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The Rack Expander will allow configuration or I/O mapping of additional modules in the local drop containing a CPU or RIO drop adapter—up to the drop word limit or physical slot address limitation.
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Option modules, such as NOMs, NOEs and CHSs must reside in the primary rack.
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Any Interrupt module can be located in the secondary rack, but the interrupt mode is not supported.
If the primary rack power supply goes OFF, and the secondary rack power supply remains ON, the behavior of the outputs on the secondary rack is not guaranteed. Outputs could either go to the Off state or adopt their Timeout state as defined by the user.
If the power supply of the secondary rack goes OFF, and the primary rack power supply remains ON, the I/O Health bit of the modules located in this rack could indicate a healthy module.
CAUTION 