(Variable) Rate control

Here is what raven does…

Looks like it’s simple string interface to send and recieve.

I know deere does something similar with grading software, I’ll look into what serial protocol they use to get rates from an external source if any.

More sources here… raven is pretty good about being open about protocols.

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I dont know of many variable rate machines that vr each section… usually they read the rate for the center of the machine (shape files have squares of certain size, usually around machine width) read that data and respond

So I would send

Header, rate, sections…(1-?) Check sum.

That way the controller knows to change width depending on how many sections are on.

The 5 different percentages are for 5 different products. The controller already knows which sections are on from another pgn.

Ah gotcha… my mistake…

So they are percentages of what?

If I have a carrier in gal/ac, and prod applied in oz/ac which one commands the %…

Ie. Running
20 gal/ac of water
32 oz/ac roundup
3.2 oz/ac bifenthren
2 oz/ac oil.

What do we base % on? If we base on water (20) then the oil will be 0.078125%

If we base on oil (2 oz) then the water will be 128,000%

So at that point why wouldn’t you just dump the number that they are (and maybe for us imperial users) and to the controller just send gallons or ounces not both…

0.015625 gal/ac in my mind is better than 0.078%

It is a percentage of maximum of the field for each product.

If 20 gal/ac is your max, it would send 100.
Let us say that the above formula is for the highest value you want to spay in the field. It would send 100,100,100,100. Now let us pretend that there is an area in the field that only needs half the roundup. Then it would send 100,50,100,100. Maybe the other chemicals need to drop to half as well, 100,50,50,50. Maybe 10 percent less, 100,90,90,90. When AOG-VR reads the kml file it finds the max value of each product. This is the bases for all the percentages. It is a percentage of the max product applied for the field.

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@SK21 , do you still have the gerber of your rate control PCB hidden somewhere? I’m unable to find it on your github. Thanks for everyones work on this, it’s going to be a popular part of AOG.

The pcbs were in the releases. I have made a separate folder on github for them. RC8 is the newest. Not tested yet.

Thank you!

Your welcome.

Hi Kent Stuff, hows the VR stuff doing? Just curious as to any updates on the mapping or building maps.

Unreal work hey!!

Couple of basic questions for you guys as I’m just in the throes of setting up the variable rate control…

Do I need the switch PCB for things to work? Or are the appropriate buttons/controls included in the ag rate app and the buttons/switches are a secondary item?

When the switch PCB is added where do I go to connect it to comms, and does it work on USB or does it only work on UDP? Currently everything I run is USB, so I’ll need a USB hub if I’m going to stay on that path.

With regards to multiple rates, I read on a thread a while back about using 2 flow meters and having rates to the left and the right of the booms for when turning, seems like a great idea!! Is that part of what you guys are thinking with the above?

With that in mind, how would the second flow rate be built, looking at the boards I see they can be addressed, does that mean I could build two RC5 boards and have one for the left booms and one for the right? Is that how you guys see the multiple rates for different chemicals working?

Thanks for all the unreal work!! I’ve learnt so much from this project!!

Built a little 4 product VR test board with 4 motors hooked to rc8 control boards and cytrons. Tried to post a little video but says not allowed here, maybe I will have to upload to YouTube or something. If anyone has a simulator field with 4 products that they would like to test I would be happy to run it. Also if there is a process for making a little 4 product map I would be willing to try to make a map and run that. Thanks


I’m in the midst of plumbing a 60 Ft 3 point mount boom sprayer on my RTK driven IH 1086. My thoughts are of building the RC8 board right away. Curious, following the pinout of the mcp23017, can i use the 16 channel relay assembly from amazon or do I have to utilize 2 of the 8 relay assemblies? Also, can I interrupt the GPA and GPB pins on that with manual switches for on,off,auto function like a typical sprayer control has? I would like to plumb this typical to section control, but have future ability for utilizing rate control also! Thanks again for all that you guys do, blows me away at the knowledge and pride that pours out of you all! Greatly appreciated

The RC8 pinout allows connecting to a 16 channel relay module. The interrupt pins are not broken out.Capture
The pins are there for relays 1-8 and 9-16.

Awesome, thank you!

Is there any way to be able to read a shp file into the VR program. Most agronomist can easily make a VR prescription map in shp format. I have played around with taking shape files into kml but my shapefiles have 4 layers of VR because I have 4 tanks with different products in them. Gets very confusing for me when trying to figure out how to convert shp to kml with these different layers within them. Any thoughts

I’ll look into it. Send me a sample.

I will get one sent to you, just chatting with our agronomist to build one for one of our own fields. Thanks

@SK21 gday from Australia. Firstly thanks for all the unreal work from you and everyone else in the group!! I’m working through building out a rate control system using your app and RC 5 board, I was just playing around with the app in simulation mode and noticed something with regards to the sections being off and the applied rate, for context my sections are 5m, 2m and 5m. when I turned the left section off the application rate seemed to start hunting which is to be expected (and a really cool feature of the simulation) but it seemed to be hunting for the same rate it was applying with all three booms on… in my case 50 litres per acre. the way I have my pipework set up is the flow meter looks at the entire flow before the section manifold. So my question is, is the flow rate when 2 or 1 sections are on allowing for the reduction in boom capacity? Or is it simply looking for the same flow regardless of the sections that are on. If the latter is the case wouldn’t that mean it would be applying nearly double to the right and centre boom in my case?

It should adjust the flow rate depending on the working width of the sprayer. If one section is shut off the working width is less so the units per minute is less, but the units per acre is still the same. I just ran the simulation with your section widths at 5.5 mph. The UPM with all the sections on was 21.7. The UPM with the left section off was 12.7. It still worked out to 50 litres per acre.