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Sarnia, Ontario | I purchased a new sprayer this year with a Raven 450 rate controller with wheel speed sensor. When driving the sprayer at 6 - 8 MPH I notice the speed fluctuates on the Raven speed display while the digital speed readout as well as engine RPMs on the tractor stays constant. This only happens about half the time. I checked the speed sensor clearance to the stud heads - about .060" - the setting in the manual. When spraying in the field if I set for 15 gallons per acre I always get more on - 15.5 -16 GPA. Anyone out there have this problem - does Raven have some bugs in the software?
Or is there some other things that I need to check?
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| Possibility the connection where the speed senser hooks into the system may not be making good contact. Have taken to greasing those pins and plugs with electrical grease with very good and lasting results. |
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Sarnia, Ontario | Already did that. When I spray out a tank load set at 15 GPA and read out the gallons used against acres applied and divide it out it doesn't always work out to the GPA setting - on my old sprayer with a 330 Raven this always worked out. |
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Bourbon,Indiana | Had the same problem with my 440. The problem turned out to be the sensor which "reads" the wheel magnets was loose and flooped around slightly. Tightened it up in the proper setting and no problems since. |
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Chebanse, IL..... | I'm sure you've already checked, but are the magnets spaced evenly? |
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Sarnia, Ontario | There is no magnets - I am assuming it is a proximity sensor which reads off the studs on the wheel hub. I checked the bracket and it is not loose. |
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Chebanse, IL..... | Jim I'm certainly no expert on anything. But-I'm not familiar w/a Ravens "proximity sensor". Could be something new. Usually you would either have: 1. Raven wheel magnets (4 of them, 2xN & 2xS) or 2. Radar or 3. GPS speed input. Here's an Adobe version of the Operators Manual for the SCS450. http://www.ravenprecision.com/Manuals/pdf/016-0159/831b.pdf Pg 34 shows procedure for mounting magnets. I think Ravens has used this same magnet/sensor setup for about 30 yrs....maybe more. Usually you can see the magnets bolted on the rim. I'm sure there HAS to be 4 of them in case of Ravens. They MUST also be mounted alternately N-S-N-S (red-black). I think that's what makes the switches work to count. Could be all wrong on all of this though.
Edited by Ron..NE ILL..10/48 6/25/2006 19:24
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Sarnia, Ontario | In the Raven owner manual it shows magnets like I had on my old sprayer - I talked to Raven tech support & he told me they use a proximity sensor instead of magnets.
I drove in the field at a steady 7 MPH on the tractor display and the raven speed readout would vary from 6.8 to 7.4 MPH. The speed on the raven should never be higher than about 6.8 MPH - don't think the sprayer was trying to pass the tractor. |
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Chebanse, IL..... | OK-then there's something new. That "proximity sensor" just reads off of anything? There was a sensor (switch) that read off the magnets. Have you not been able to calibrate either speed or flow meter to make things come out right? They should be 2 separate issues. What I usually do to calibrate gs part is to drive a mile (5280') to calibrate distance (g.s.). I know the book talks about 400', but seems to me that 13x that distance ought to even out the bugs a little. Ravens gives formula in manual for calibrating distance (gs). Flow meter gallonage can be a little trickier. You have to come up with some type of known gallonage. I think plastic tank mfg warn that they can have up to 10% variance in their markings. Also-one has to consider whether the tank has been drained 100% wheni it's empty. Usually not. Ravens gives formula in that manual for calibrating flow meter also. Sounds like you're only 6% off in gallonage (flow meter). GPA will be a combination of distance & flow....or their errors. Actually-one error could nullify another. After calibration-the only thing that could throw off flow would be something obstructing the flow meter turbine wheel or air bubbles. I guess your proximity sensor could be picking up something else also? Good luck there. |
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| We have a proximity sensor on our 3 year old sprayer also. This year the speed would read erratic every so often causing the pressure to jump up and down. We tried the connections and added bigger studs for the sensor to read off. This worked for a week and started acting up again. We put a new 125$ sensor on and it has worked fine since. The way I understand it there is a magnet in the sensor that gets weak causing it to read wrong. |
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Near Intersection of I-35 & I-90 Southern Mn. | To compute the applied rate accurately both the Flowmeter and Speed Sensor must be calibrated properly. The Rate per acre is determined by the flow per minute and the acres per hour. If you ever see a Rate of zero when in fact you are applying - check the Vol/Min and the Area/Hr. One or the other will be zero. This will help you in your troubleshooting efforts.
As has been noted, to check the Flowmeter involves knowing "how much has left the tank" and comparing it to total volume. Knowing how much has left the tank can be tricky since the tank markings are generally not very accurate and the tank is usually not completely empty. Weighing the tank empty vs full and using the density of the product is another way of computing the Meter Cal. Generally the number stamped on the tag is plenty good.
The speed sensor that you have is apparently the proximity type. I have installed both the proximity type and also the older magnetic type that Ron refers to. I much prefer the magnetic type as they are more troublefree but sometimes harder to install and maybe more expensive. I personally use a magnetic speed sensor although I have radar and GPS available.
The bottom line is to get a speed sensor that is reliable and calibrate for a field of known acres.
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Oswald No-Till Farm Cleghorn, IA | Hi,
I have a Raven 450 and like it mostly but have seen the very thing you notice. On average, I come out pretty close to my goal rate. I have the proximity sensor. I have suspected the sensor but haven't gone to a new sensor as I might just use the GPS for speed.
The Raven 450 is tied into my AL PF Advantage to log onto the card. Those acres vary slightly.
Best of luck. I have run Raven 440, now 450 since 1984 so really can't comment on anything else.
Tom
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Raven 450 SCS Rate Controller
