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firmware version v. 17 - 20
battery back-up of user application
CompactFlash for backup non-volatile memory
1756-L7xS vs. 1756-L6xS
firmware version v. 20+
non-volatile memory is SD card instead of CompactFlash
Replaceable Energy Storage module for battery back-up of user application
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firmware version v. 31+
Non-replaceable Energy Storage module for battery back-up of user application
Safety Signature has changed instead of 32-bit hexadecimal value it is a 32 character hexadecimal value stored as a SINT(33).
Built-in Ethernet port
Task Monitor Tool do no longer works. To get similar data there is a web page on the controller itself.
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