Output does not energize

esp400

Member
Join Date
May 2015
Location
Milwaukee
Posts
69
Hi All,

I've been programming RSLogix 500 for about 5 years now and I'm just getting into 5000 programming. One of my first projects here where I work was to mod a few buttons that drop printer programs into a laser printer. It's a pretty simple process where a few bits are set by a button, you press another button to have the laser read the bits, then unlatch everything after a period of time has elapsed so that the printer I/O can settle. However, it doesn't work. I've posted a screenshot of this. I'm going to preface everything by saying that I've searched for the ONS and the OTL in the screenshot to ensure they are not anywhere else in the program. Also, I had the OTL in the program as an OTE before and I changed it just to see if I got better results (which did not happen). I've tested the buttons live and watched the entire rung go green with the exception of the output. Anyway, if anyone has any suggestions on what I might look into, please feel free to chime in.
 
Silly question, has that particular output been used anywhere else in the program? If so that rung may leave the output at 0, the your marked rung may become tru but the output may stay 0 as it has been used twice.

Just a thought, ...

Stef.
 
You know this most likely, but have you looked for word access on that address?

I've seen in other places where bits are cleared via a FILL instruction or just a normal word or integer access. Perhaps that's what's going on?

Is there a chance that the tag can be overwritten from another PLC?
 
Few silly questions
Is your program being called?
Do you have any jump/label logic.

Add a counter in parallel with you OTE/OTL instruction and see if it will increment.
 
We would need more of the program to know for sure. It could be multiple destructive uses as stef mentioned. It could also be that super quick timer constantly timing and resettng. We could speculate all day.
 
I will add the counter and see if it increments to ensure that the right side of the ONS works. I know the rountine is being called because it's in a rountine that was being called before I modded it. Not sure on the FLL instruction but I will look into it but it seems unlikely. I will try and post the program.

Thanks!
 
I've searched for the ONS and the OTL in the screenshot to ensure they are not anywhere else in the program.

just a GUESS ...

try using the Cross Reference feature instead of a search ... in RSLogix5000 a bit/address can have multiple aliases/tagnames ... a Find All Search won't show all of these - but a Cross Reference will ...
 
If you have ONS before your OTE you will never see your OTE being energized. It will go on for one PLC scan and then off. If you have OTL it should work though.

So first to check is if your rung being executed. If it is then there is something that is overwriting your output.
 
First off the plc in the screen shot is offline, second, is the OTE/OTL being unlatched elsewhere in the program, or, is it a bit within a word and that word being written to elesewhere?

Steve
 
Thanks for all of the replies. I have it figured out. The timer was set too low. I changed the output back to OTE. I appreciate all the help. Still getting my bearings working within 5000. Prolly a rookie mistake.
 

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