Hello, I have a John Deere 6140R, and also a John Deere 2630 display and a Starfire 3000 with RTK that I use for autosteer in it currently. But I have the occasional need to use the 2630 in the tractor and combine (9870 STS) at the same time, and I’m exploring the use of AOG in the tractor instead of buying another Deere system.
Looking at the parts diagrams, this tractor already has a dedicated hydraulic valve block for autosteer. I’ve read threads on here of others putting together their own hydraulic steering valves, but in this case that would be redundant. Has anyone actually controlled a John Deere steering valve with AOG? I’m not opposed to building my own hydraulic valve setup or using the electric motor on the steering wheel, but I really like the idea of using the integrated system if possible.
The part number of the valve on this tractor is AL229994. It appears to have one solenoid that I expect is PWM driven. I believe it has pressure and return lines from the rear of the tractor, and then simply tees into the steering cylinder lines that come from the manual steering wheel valve.
I don’t know a whole lot about PWM systems, but if I could generate a PWM signal I think I’d be able to tinker with it and try to actuate the valve. I have an Arduino, but I’m not sure how to take a PWM output from that and turn it into something that can move a hydraulic valve. I would appreciate any guidance on how to accomplish this. Thank you!
Also, I’ve ordered parts to build the PCB v2. Reading further on the Wiki, I see the BTS7960 motor driver is listed for controlling a proportional valve - I am guessing this is the part I need to experiment with the tractor valve.
For the motor/valve driver I prefer the cytron MD13S.
Are you planning always using AOG or only when the JD already in use?
You will also need a wheel angle signal, probably you can take signal from the OEM in differential mode.
For a clean install with a hydraulic valve you should use the steering wheel encoder to cut off the valve. I don’t know if you can simply tap in to use the signal.
If you want use both AOG and JD I think it is possible to use the oem valve if you can switch the leads from one system to the other.
I will follow is tread, I will maybe install an RTK AOG on a JD6430 that run with a Starfire 3000 with SF1/SF2 most of the time. AOG for steering and JD for mapping.
Are the Cytron MD13S and the BTS7960 basically interchangeable in this application? I like that the Cytron fits onto the PCB v2.
I plan to use the Deere system primarily and only use AOG when I need the Deere system in the combine (the 2630 is needed for yield mapping as well as autosteer there).
I am hoping to use the OEM wheel angle sensor by reading its signal in differential mode as you describe, and I would like to use the OEM steering wheel encoder also if possible.
I’ve been reading on here about Deere steering valves, and I looked at the links that Pat posted. But those are all Danfoss valves. I’m not seeing anything that looks like that on this tractor. See screenshot from the parts diagram below. I’ve looked through the whole steering system in the JD parts catalog and I don’t see anything that looks like a Danfoss valve head/controller. That’s what makes me think I need to drive this valve directly with PWM, and I’m wondering if anyone has experience with this type of valve from Deere.
Where is your valve located? On the steering orbital from factory? Or is it mounted under the cab behind the steps on right hand side? If the latter its most likely been added as autosteer kit after factory?
Those valves may be PWM possibly, get a photo of the valve block / harness that goes into it.
The valve is under the cab on the right hand side. It came that way from the factory - we ordered this tractor brand new. I won’t be near the tractor for some time, which is why I’m relying on the parts diagrams. We also have a 2014 7230R (newer generation). I can’t find a Danfoss valve in those diagrams either. I’m wondering if Deere moved away from Danfoss in the 2014 and later tractors and is doing the PWM control on their own in the Autotrac system?
Anyways, no big deal if it isn’t a Danfoss valve. I’m hoping it can be controlled by the Cytron MD13S. I was able to search for the part number on Google and find some images of the valve, if anyone can tell me more about it by looking at them. There are 3 solenoids - looks like steer right, steer left, and enable. I can’t see the pins, but based on the size of the connectors I expect they are only 2 pins.
I guess where this really leaves me is that I need to figure out what types of signals the tractor’s Autotrac controller is sending to these valves to make them work.
It seems there would be 2 different ways to approach this:
Probe the wires on the valves to try to understand what’s happening when the John Deere autosteer is active. Would I need an oscilloscope to do this well? Or, I’m wondering if I can hook a multimeter in series and measure current and get meaningful information? In the latter case, I wouldn’t get any PWM-specific data, but it would help understand the current range the valve uses and how it varies in different steering events.
Build my PCB v2 with a Cytron motor driver and try a bunch of different PWM currents to see what makes the valve move.
Hello,
Yes, I would like to do the same. I already lookt at it a bit but not much to find about those valves. What I noticed, when disconnecting the plug from the solenoid jd gives an error. So we also need a resistance to simulate there is connection.
We would need to know the resistance and voltage of those solenoids to power them up.
Also find a link to buy those plugs and pins for good connection.
Alexlan, what tractor do you have? Mine is a 2014 6140R with the 50k IVT transmission and has the Autotrac-ready option from the factory. I am wondering if we have similar tractors and have the same valve.
@rynthln, mine is a 6150r also from2014 I think. the valve is very similar to the one in your pictures, propably the same. Unfortunatly I don’t have the green star anymore to messure the pwm or other signals, ours where stolen. I decide to make my own system with AOG. At the moment I use a motor on the seeringwheel, It works fine but If I can make it work I prefer it that way and use that for an other 6170r that doesn’t have a valveblock.
By the look of the pictures, the 2 grey (A and B)valves are the proportional, and the black is on/off
When you read the voltage you would get 12 v on the black and between 0 and 12 on the greys.
More correctly Ampere makes the magnetic field in the coils, but A is a result of Volt and that is why it is enough with a motor driver like MD13s that gives more volt the more PWM it gets.
The frequency is not that important but helps the valve to not “stick” and as you can read in other treads here it seems frequency do not need to be very high. I would suggest entering “Hydraulic pwm” in the search field to read more.
Thank you, this is helpful.
One question on current for my curiosity - the current through the coil will vary with coil temperature, correct? And AOG does not compensate for this since it’s sending a voltage PWM signal?
Yes it would vary, but not significantly enough to worry about or to require a change in PWM signalling. I think if it gets hot enough to change resistance significantly, you’ve got much bigger problems and a fuse would be blow anyway (or the coil or motor would be on fire). I’ve never heard of anyone worrying about it.
Debates get serious on much less significant topics. Do you mean current control instead of voltage control because of the coil resistance change from temperature change?
Ignoring the dynamic behaviour (because of inductance), as torriem mentioned, the difference between current drive and voltage drive must be insignificant.
Perhaps it would make sense to try to estimate oil flow changes at different coil (valve) temperatures but that is independent of the drive approach.
I think that due to many factors that affect the final control effect, I would consider the problem of hot coils the least important. For example, the oil temperature will certainly have a much greater impact on the flow, probably with increasing temperature its viscosity will decrease and thus the throughput of the valves will be higher at a given opening, if at the same time the valves will open less because of hot coils, it will even compensate.
