Control logix I/O

Im used to working on AB PLC5, and have some experience with control logix processors.
My question is in control logix is there an easy way to see what inputs and outputs are free, like in plc5 you can goto the data table and look to see what is used then search the program to see if that address is used in the program anywhere.
I have read alot on control logix but dont really understand how this is done easily. any help appreciated.

Look in the tag browser and select 'Unused' at the 'Show' drop down.

sorry - but the “Cross Reference” is probably as close as you’re going to get to a “usage” feature ...



notice that the “Name” field is NOT set up all the way down to a “bit level” address ... and notice that the bits are sorted “alphabetically” rather than by their “numeric values” ... so bit “.10” shows up ABOVE bit “.2” (because 1 comes before 2 alphabetically) ... that little trick makes it easy to look down the list and see bits 7-8-9 listed - and then assume that bit 10 must still be available ... that could be bad ...

hope this helps ...

Thanks alot for the help.

something new? ...

Greetings averytc ...

Look in the tag browser and select 'Unused' at the 'Show' drop down.

Click to expand...

what version are you using? ... every time that I’ve tried that trick, it regards the whole tag as “used” if ANY of the bits have been used ... in other words, if even ONE bit from a module is used, then none of the rest of them show up ...



if you’re somehow getting this to work, I’d love to know the trick ...

Hi Ron,

I've not been able to make that work either, but I forgot that fact when I posted. The only time it really matters for me is on one-shots. I've got a few words in each routine for one-shots ('routine_ONS'), and for thoughs I lable them as I use them. Otherwise, I normally create only what I need. I do miss the 'next unused bit'...

Charlie