Adding new Card(s) in 1734 Point I/O Rack

[DRGNBTR]

Hello,

Fairly new to PLC programming. Have a question in regards to a 1734 Point I/O rack and the built in tag structure in Logix Designer.

I have a rack of 12 Point I/O cards and I need to expand the rack and insert two more cards at rack index positions 5 and 8. The current cards in those slots are type A and the new ones will be Type B. I can't seem to change the card type at each slot position in the I/O configuration so I have to delete them and re-add them as the proper new type. The code I inherited sometimes directly references I/O which means any rung that points to a bit that's shifted in the rack now points to the wrong bit.

Is there an intelligent way to add an additional card into a Point I/O rack but shift all the Raw and Alliased tags along with it to not destroy the I/O mapping or must this all be done manually?

Thank you!

 

[plvlce]

Don't delete anything unless you are removing a card completely. Increase your chassis size from 12 to 14, then individually change the slot # for each card to its new position. It won't let you assign to an occupied slot, so start at the end moving 10 to 12, then 9 to 11, 8 to the now unoccupied 10, etc (assuming ordering is being preserved). Make sure that your changes in the program match your actual changes in the field, leaving positions 5 and 8 unoccupied. Then create your new Type B cards in those slots.

I believe that when you change the slot in the module definition, the program will automatically shift the tags to use the 'new' position.

Disclaimer: I've never actually done this with 1734 modules, but quick testing suggests it should work and I *have* done it with 1769 I/O modules.

 

[DRGNBTR]

Beautiful thank you!! That works exactly as you described and its smart enough to re-index existing tags (both base and aliased) to the "moved to" locations in the new slots.

Thanks again.