What is the difference between a 1756-L62 A and a 1756-L62 B ?

Good Evening ,

Could you folks tell me what the difference is between a 1756-L62 A and a 1756-L62 B ? I found a 1756-L62 A , but all the CPU's that I have in operation are B's . Is there any major differences ?

Thanks so much ,

They are physically slightly different; the CF card slot was moved from the bottom to the front, the serial port is in a different location, and they use slightly different RAM backup batteries.

But logically they are identical; Series A and Series B controllers will all run the same firmware, and you cannot tell them apart in software.

From the Rockwell KB:
1756-L6x Controllers: Difference between Series A vs. Series B
43312 | Date Created: 09/18/2007 | Last Updated: 01/11/2018
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Question
What are the differences between a Series A and Series B ControlLogix L61, L62 or L63 Controller?

Environment
1756-L61
1756-L62
1756-L63
1756-L64
1756-L65
Answer
There are two hardware changes to the Series B controllers:

New battery circuit for extended battery life. Uses 1756-BA2 "blue shrink wrapped" battery.
Compactflash card slot relocation under front swing door. Now the CF card can be removed without pulling the processor from the chassis.

Edit: Ken beat me to the punch.

Thanks so much for the information. Have a good weekend .