Output not "outputting"

[gappvembe]

[RSLogix 500]
[Micrologix 1000]

Here is an odd problem I've come across.
An output that turns a hydraulic solenoid on (which in turn makes a shaft go "up"), isn't working in it's normal means. The rung is made true, but the output doesn't come "ON". I can force it ON and it will work, there is also a switch that puts voltage directly to the solenoid and that will make it work. For whatever reason when T4:0/DN is made (which is all that is needed for the rung to go true, shut off the down solenoid output and turn on the up one), nothing happens.

Anyone ever come across something like this?

 

[Kidblue]

Is the state you posted in your screenshot the state you are trying to diagnose? The output you are trying to energise is being reset by the 'Crusher UP L/S' (or have you snapped the code in a rested state?)

Check the rest of your code if O:0/9 is being unlatched anywhere else when you are trying to energise it (even at the word level).
Is this new code you have written? Are you actually scanning that particular data file?

Regards

Rob

 

[gappvembe]

Is the state you posted in your screenshot the state you are trying to diagnose?

No it's not. This is just from the program file saved on my computer.

The output you are trying to energise is being reset by the 'Crusher UP L/S' (or have you snapped the code in a rested state?)

I would guess rested, like I said above, its from the file on my computer. I did get online with the machine and watch it run, when T4:0/DN would go true, O:0/8 would not shut off, nor would O:0/9 come on.

Check the rest of your code if O:0/9 is being unlatched anywhere else when you are trying to energize it (even at the word level).
Is this new code you have written? Are you actually scanning that particular data file?

This is not new code, as the machine and program have worked properly up until this point (not sure when the last time it was ran. There is no other unlatching (that I can tell anyway) anywhere else in the program.

Regards

Rob

Thanks

 

[Bob O]

As Rob mentioned check the state of I:0/6 and also make sure T4:0/DN is going true. To do this you could add a counter to the rung to make sure T4:0/DN is going true/high.


Hope this helps.

 

[gappvembe]

I just checked on the machine... it's working fine now.
Like I said, an odd problem.

 

[leitmotif]

Logic seemed OK and you have confirmed that by now have it running. Saw no indication of limit switches so probably not sticky limit switch.

I assume you are using compressed air. Solenoid valves and pistons need dry air ie no water. Also they will run much better with a little lubricant ie oil. Doesnt take much two or three drops per day seems to be fine.

 

[jrwb4gbm]

While the machine is running, is the physical Input I:0/8 (Can in place) de-energizing, and also, is physical Input I:0/6 (Crusher is up) energised to allow Timer 4:2 to run? I suspect the most likely cause of the problem to be a failed or intermittent device connected to these Inputs. If it were me I'd replace both devices and check for loose connections or physical damage all along the wires.