lazer 4000 problem

[waright]

some passes, not all the time, the bridge will run all the way to the rear limit then send the trolley across and continue the wash. Sometimes the bridge stops early, going forward direction or reverse direction, the arch turns, then the trolley runs the arch into the side of a car. It has impacted the drivers side and the passenger side. I found that all the tbar eyes were spliced, so we put on all new eyes. same results. The front limit, the middle flag, and the rear limit all seem to be working. I've stood in front of the jo box and watched the inputs for these and they all seem to come on at the proper time.

What am I missing? thanks for the help.

 

[MEP001]

Does it happen only on pickups? Some trucks have a gap between the cab and the bed so wide that the eyes "see" between them.

 

[whitescout]

Check your middle limit prox switch and cable. The middle limit switch turns on the front eyes as the bridge is travelling forward, and the rear eyes as the bridge is travelling to the rear. they share the same input.

 

[waright]

problem is not related to vehicle type, size, pickup

i was thinking mid limit as reason why it would travel full length sometimes, but does mid limit explain stopping too soon and turning into the side of vehicles? thanks for the responses

 

[madscientist]

If the bridge is going all the way to the end of the rails after both sets of t-bar eyes are exposed, then it is not a mid limit issue. Or, I should say, it is certainly not only a mid limit issue. A faulty mid limit would make it read the front eyes when it should read the rear eyes, or vice versa. It will not make the bridge go all the way back, or make the bridge stop too soon. Faulty Front and Rear Limits will do that.

When you replaced the t-bar eyes, did you splice new ones on? Or did you replace the entire length back to the box?

 

[waright]

eyes replaced all way back. previous service company had them spliced (poorly) in the tbars, but i guess they had been that way for years.

thats what i don't get; it will wash perfect one lap, the next lap it might go all the way to the rear limit and continue washing, without any errors, then it might be perfect the next lap, or it will go alll the way to the rear limit again.

If the vehicle strikes only happened on one side, i could figure on replacing the corresponding limit switch, but it has had impacts on both drivers and passenger side.

 

[boywonder]

Bad amp, or festoon wire

 

[koliver]

The Machine will go long or stop short for several reasons. If there is a short either on the front or rear limits, or the t-bar eye input, the machine will stop early. This could be a short with the switch, cable, terminals, or festoon cable.

The machine will go long if there is an issue with the machine seeing the mid limit flag or t-bar eye input. When the mid limit flag is see it will make the t-bar eye active. If mid limit missed, the eye will never become active. This could be caused by the machine “walking” down the rails due to a mechanical problem with the rollers, tires, or rails. Also, a missed input could be caused because of the switch/eye, cable, terminals, or festoon cable.

Most intermittent problems can be traced back to the festoon as this is one of the most wearable items on the machine.

 

[waright]

thanks

festoon is less than 2 years old, so i don't think it would be this.

i've had problems with carlo gavozzi amps and gavozzi relay bases before at other sites. I bet it is a bad amp or socket.

thanks Kris, I wasn't thinking that a bad input from the tbar would stop the bridge short of the end of the car, I was only thinking the lack of a tbar eye input would cause the bridge to go long. I would have replaced a end limit prox already, but the vehicle strikes have been on both sides, which means that both limit proxes would have sent false inputs into the plc and i think that this is too unlikely.

we appreciate the help.... I hate to just start throwing parts at it until the problem goes away.

 

[waright]

problem has been solved by replacing one of the tbar amps.