Left side measure on LW 4000

[getnbusy]

How does the left side measure operate on a LW 4000 with VT ???

 

[getnbusy]

I had a pretty lengthy exercise on the VT system last month, but I never asked any questions about the left side measure. I'm just curious of the sequence of events and how the machine determines the left side. Specifically, how does the machine transfer info from the sonars, thru the VT, and out to the bridge ???

 

[newhampshiretech]

to the best of my memory, the sonics once calibrated, sense the vehicle as it enters the wash this "measurement" is taken in directly by the vt board, the vt board deciphers the measurement and equates that to how many of the pulses on the x30 it wants to see as the trolley moves right to left across the front of the car. so as the trolley starts it creeps right based off the right sonic measurement, then stops briefly (right front fender area) then moves right to left across the front of the car passing the reader bar flags or whatever you want to call them on the interior of the exit side rail inside of bridge, after it passes the number of flags it feels correlates to the measurement it received it will stop , rotate the arch then travel down the drivers side. I believe at this point the wash continues its left to right measuring by counting the x30 pulse up and down for the duration of the wash, just meaning if it went 15 pulses 1-15 from right to left ,, it gets to the rear of the vehicle and travels left to right 15 pulses. thats why if x30 is bad or the flags are rotted out it may be at all different extents off the side of the car during a single wash , and or hit the t bar, or turn before it even clears the car etc. I apologize Im pretty long winded in my responses.

 

[getnbusy]

Thank you NHtech. That is the way I understand it as well. I am wondering tho, how come you cannot see the prox or input card light up as the machine moves around on the driver side of the vehicle ?? That part is not making sense to me.

 

[newhampshiretech]

well if you are in the bay you should see the prox switch itself light up. But I believe the input gets taken in and dealt with by the vt in a different way. the reader flag used to only be on one side and I think I was told that the software in the cpu would need to be re worked to deal with dual reader bars and the a5000 was at its max for memory useage so they built the vt to be the middle man, a little computer to fake out the big computer in a sense. so where the the a5000 couldnt do the computing for the measurements the vt does and rather than sending x30 pulses from both reader bars the vt deals with it directly, because I think if the a5000 saw the extra set of pulses from the secondary flag it would not know how to compute those as an input. it was only ever capable of measuring the right side and going all the way to the left where the tire was in a treadle and therefore a known position. so I think in essence the vt probably just throws out a left limit flag pulse when it is happy with how many x30 inputs it has seen on right to left movement

 

[getnbusy]

that is the way I understand it too. On my machine, the prox switch does not lite up on the drivers side of the car. The VT works, but that prox does not lite up on the drivers side. I dont understand how come. Any other thoughts ???
thx

 

[newhampshiretech]

no idea, I mean the proximity switch is powered as long as the machine is on, and when the internals see metal it should close the contact and the light on the switch itself glows as an indicator, so you should be able to put the trolley anywhere left to right and whether its a flag in front of it or you put a screwdriver or knife in front of it , it should light up. it gets its power from I believe wire 4 and 5 in the blue festoon, which is a 24p, and 24n the same that are jumped to power x15,16,17, 22 30 etc etc , so in theory while the laserwash is powered up the x30 prox is live and the light should light whenever it reads a flag or any metal, if you are saying that the switch lights fine on the passenger side and does not on the drivers side , it would either be , a loss of power to the prox switch or the distance to the flag , so as a test . if you drive the trolley manually far left drivers side and put a piece of metal in front of x30 does the light on the actual switch itself glow? it should . if it does not then you have an issue maybe a bad wire somewhere. or I have seen steel flags on passenger side and stainless on drivers side , the stainless requires the prox switch to be much closer to it to read. etc.

 

[newhampshiretech]

now that is to say that the switch in the bay itself should always light when introduced to metal, but this signal travels in through the vt board and then back out to the input card , so you may not always see the x30 on the input card in the jo light all the time. because the vt is sending that signal as a middle man when it wants the jo computer to see it ,

 

[getnbusy]

Ten 4 NH. I am following you 100%. No kidding, mine works fine on the passenger side and any time you put metal in front of the prox., b ut it does not work when passing by the pulse bar on the driver side. YEs the PS is steel, and the driver side is stainless. The prox is adjusted extremely close on the driver side but I am guessing that it is maybe not recognizing the stainless pulse bar. Is there a remedy for this problem ??
thank you
Bob

 

[old guy]

If you turn the selector dial to position 3 on the VT board [this is where you can watch the inputs] light #8 is trolley prox 30. See if this light comes on for each flag of both pulse bars. The pulses from the drivers side pulse bar are not passed through to input 30. The VT counts the drives side pulses and then sends a left limit input when it wants to stop the trolley at the left side of the vehicle.

 

[getnbusy]

I preshate that old guy. I will check on that first thing in the morning.
thank you