[Logix] Add On Instruction error (missing output instruction)

With AOIs in Logix5000, I'm noticing that if I create an AOI and populate all the parameters, I'm still getting an error that says "missing output instruction". Further, the AOI is on the far left of the ladder rung, which makes it seem like it indeed is expecting some sort of output instruction. The odd thing I can't figure out is that AOIs from AB (like the SCL (scaling) AOI) are perfectly fine being the only element on the rung and hang out on the far right, and require no output instruction. I've checked all the settings and even went to far as to copy the SCL_AOI, gut it, and put my logic in it...but no luck, it gets the same error message and is on the far left of the rung. I've read on the forum that putting a NOP instruction will solve the problem, but I wanted to ask if I'm missing something; since AB's AOI can work just fine, why can't mine?

My AOIs work just fine by themselves and end up on the right side of the rung whenever I add them. I wonder if it has something to do with the way your AOI parameters are configured.

scameron81 said:

My AOIs work just fine by themselves and end up on the right side of the rung whenever I add them. I wonder if it has something to do with the way your AOI parameters are configured.

Click to expand...

I think it was the way it was configured; I realized I only had inputs. After I added outputs, it works as I'd imagine (right side of rung, no NOP needed). I think that was the cause. Thanks!

Yes, your findings are correct...

If an AOI only has Input parameters then it will be treated as an Input instruction and will be placed to the left side of an empty rung. Without an Output instruction on the rung it will not compile.

As soon as you add an Output parameter it will be treated as an Output instruction and will be placed on the right side of an empty rung and will compile.

This is confirmed here...

53889 - Error Message " Missing Output Instruction " when using an AOI (Add-on instruction)
Access Level: TechConnect

Regards,
George

Geospark said:

Yes, your findings are correct...

If an AOI only has Input parameters then it will be treated as an Input instruction and will be placed to the left side of an empty rung. Without an Output instruction on the rung it will not compile.

As soon as you add an Output parameter it will be treated as an Output instruction and will be placed on the right side of an empty rung and will compile.

This is confirmed here...

53889 - Error Message " Missing Output Instruction " when using an AOI (Add-on instruction)
Access Level: TechConnect

Regards,
George

Click to expand...

Great info, thanks George!