Cannot find where OTE is generated from

I am relatively new to PLC game. I have a SLC 503 and am trying to find where or how a particular output is turned on. When I do a find all I just find XIO and XIC's for this output. Where could the OTE be or how could I Find where it is generated. thanks

The find all will only find 'direct' references to the output. If the output is used in a sequencer or indirectly it will not show up. Use the 'cross reference' for the point instead and it will show if the whole output word is used as well as each bit.

Don't forget external sources

grs is right about cross-reference and bits being set at the word level.

You can also go to the data table (looking at it with the Binary radix), and press the USAGE button. That will tell you if there is a word-level (a "W" in left margin) and also at the file level ("F" in the margin).

It's also possible that bits may be set by an HMI, SCADA or another PLC. You'll NEVER find those, no matter what search method you use.

Then there's indirect addressing. Searchin on B3/0 may find the contacts, but it will never find OTE B3/[N7:11]. The cross-reference may help there. After checking on the word address, scroll to the last part of the file listing (alphabetically, B3/[N7:11] comes after B3/999)

Thanks for your reply grs
I did across reference and shows just the 4 XIC's?? thanks

help

in the binary radix usage there is a W in margin. still unable to find OTE. This output I am talking about is the reverse for a VFD.I see the XIC's change state and the drive is reversing. Any thoughts on how I could find OTE would be greatly appreciated.

Greetings clank,

the "W" indicates that this address is used at the "word" level ... try searching for your mystery bit as part of its word ...

example: if looking for "O:3.0/12" try looking for "O:3.0" ... something like an MOV (Move instruction) could be operating on the whole sixteen bit word ... and not on the individual bit the way an OTE would do ...

if all else fails, post your program and we'll help you track this down ... this post should help you make the post ...

and welcome to the forum ...

It could be a possibility...

Out of curiosity...what is the address that you are trying to find? Are you sure that it is the reverse COMMAND for the drive? It crossed my mind that you may be looking at the cross reference for the reverse STATUS of the drive, in which case you probably won't find any OTE instructions for it.

How is the drive communicating? I/O modules? Network? What network? What address are you looking for?

As Ron mentioned, post your code and we'll see what we can find.

grs