intermittent wash stopping

[bridgescarwash]

We have an Autec machine that is intermittently stopping during the wash cycle and sounding the exit alarm. We are not getting any error codes. This is happening consistently, sometimes every 3-4 washes sometimes only once every 25 washes. We have checked out treadle eyes and backup bell eyes and dried the connections and made sure they were greased(dielectric). Just looking for ideas, we are chasing a ghost on this one and really pissing off some customers. Thanks for any suggestions.

 

[Blanco]

You need to be there and watch the PLC when it faults. The machine only does what the PLC tells it to. Watch the inputs and outputs. It should not be too hard to figure out considering how often it’s happening.

 

[bridgescarwash]

You need to be there and watch the PLC when it faults. The machine only does what the PLC tells it to. Watch the inputs and outputs. It should not be too hard to figure out considering how often it’s happening.

That’s the problem, we aren’t getting a fault.

 

[Blanco]

Like I said watch the inputs and outputs. That’s what tells you what the machine is doing. You don’t need to get a fault to figure it out. I was just saying when it does fault/stop working look at your plc to see what it’s doing.

 

[Waxman]

Is the fault at the same pass within the wash process every time it faults ( hi pressure, scrub, low pressure, etc) ?

If so, determine what inputs are lit normally during that step in the wash cycle. Observe the wash and see which inputs are not lit that should be lit and go from there. I have had inputs 'flicker', indicating a bad wire, prox switch, cable end or connection ( different machine, not Autec).

 

[bridgescarwash]

Is the fault at the same pass within the wash process every time it faults ( hi pressure, scrub, low pressure, etc) ?

If so, determine what inputs are lit normally during that step in the wash cycle. Observe the wash and see which inputs are not lit that should be lit and go from there. I have had inputs 'flicker', indicating a bad wire, prox switch, cable end or connection ( different machine, not Autec).

No we aren't getting a fault. Will kick people out during different times in the wash cycle. We are leaning towards intermittent power loss on the treadle eyes. We are going to rewire next.

 

[Blanco]

If you can't be there and watch it then put a camera in the bay and a camera on the PLC. Once again you dont need to get a fault to fix this. WATCH THE INPUT AND OUTPUT LIGHTS. That will tell you what it is doing. When you have a fault/malfunction look at the time it happened in the bay then check your camera on the PLC to see what lights are on or off that shouldn’t be. I dought its your treadle eye wires and instead of wasting money and more importantly time rewiring you can simply test that by setting something to block them and watch your PLC to see if your treadle input light is steady on or if blinks occasionally. For this to happen every 3-4 or 25 washes you should be able to figure out pretty quickly. Don’t just throw parts at it for no reason you need to watch your PLC.

 

[kentadel]

Is there a multi conductor wire traveling with the machine? It's possible you have wires rubbed bare, shorting, and causing a fail. Like Waxman and Blanco posted look for flickering inputs and outputs. Been down that road before.

 

[bridgescarwash]

Thanks for the suggestions guys!