RAM vs EEPROM?

david90

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Join Date
Apr 2010
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ca
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What are the advantages to storing PLC programming in volatile memory instead of non-volatile memory such as eeprom?

why do control logix processors store plc programming in RAM and keep it alive with a battery instead of using flash/eeprom memory?
 
This is a (badly worded) homework question.

What are your thoughts. ?
 
For the same reason I keep my pencil on my desk instead of locked in a closet across the room.

The modern ControlLogix controllers (the 1756-L6x Series B and later) gather up all their pencils and lock them in the closet when you power them down; they just need a little power from the battery or from a big capacitor in the Power Supply module to perform that storage for a few seconds. When they power back up, they take all their pencils out of the closet.

The newest CompactLogix have an "NSE" version without a capacitor in the power supply module so that it goes to a "no stored energy" state for hazardous atmosphere use. Bring that up for extra credit !
 

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