This particular subject doesn’t pertain to AOG exactly, BUT there’s a lot of great info and people on here so I’d like to brainstorm if you’d let me.
I’m getting an Ag Leader system with Steer Command Z2 for my 4WD tractor that runs the planter. I’m looking at options for a steering valve, as unfortunately at the moment, Baraki doesn’t offer a OC 60 liter valve yet. I’m sure he may in the future, and when he does I’m going to get one for my other 4WD, but I need a valve for my planter tractor soon. I’m looking at getting a Danfoss EHI valve that uses the PVED-CLS controller.
Here’s my conundrum. This tractor is old, so it obviously has no CAN system. Ag Leader offers Z2 controllers that are CAN/ISO controlled for newer tractors that are steer ready with CAN-BUS. I may be thinking of this too simply, but can I hook the CAN plug on the Z2 controller to a makeshift CAN-BUS (twisted pair of wires with two resistors) and hook the other end of the BUS to the CAN-H and CAN-L pins on the valve… and it actually work??
This is all assuming I have power ran to the valve, a steering angle sensor, and there’s a good amount of setup in the valve PVED-CLS software alone (plus the Ag Leader system setup too, but that’s pretty straight forward). Is this as simple as I’m making it out to be, or is there a lot of info that I don’t know that’s going to make this not feasible at all?
Well the PVED-CLS uses CAN to communicate. IF it’s as simple as I’m thinking, I would be able to use any guidance system that uses CAN to communicate including AOG… right?
I am sure someone else know better than me, but I have some questions. Can message from WAS if no tractor computer in between? The aog communication to and from tractor computer?
I theory you are correct, you should be able to use any guidance system that has can support for the pvedcls. For example I think with agleader you may need to select the agco autoguide valve type.
The pved-cls is used on a number of main brand machines that can be steered with alot of different systems.
From what I know of the ehi with pved-cls there are a lot of different configurations and to configure the pved-cls part you will need help from danfoss with codes to access parameters that you will need to change. The pved-cls needs to have vehicle speed on the canbus for it to work properly too so in your situation you need to find some way to do this. The WAS can connect directly to the pved and you need to either have the sasa sensor for manual override or get the ehi with hydraulic override.
I haven’t used the ehi/pved-cls as a retrofit valve but have looked into it and those were the things that had stopped me along with the cost.
Okay, so connecting to the valve itself probably isn’t the issue, it’s other things.
The past week I’ve been reading the setup manual for the PVED-CLS, and I’m starting to understand everything that is needed to configure the valve. There’s software that you download on your laptop, then download a free license to use it, then get an adapter to connect the laptop to the CAN-BUS. (They also have video instructions on how to build an adapter cable yourself, which I thought was very neat that they actually offered that as an option.) Then you can reference the manual which tells you what every parameter is, what it does, and what they recommend from the factory. I’ll try to drop a link down at the bottom for the manual.
I didn’t know it had to have a speed sensor, I’ll have to look into that one. It would be great if I could send out speed data from the GPS itself on the CAN-BUS, but I have a feeling that would be way over my head.
Connecting the WAS directly to the valve is great, because that alows for a feature the valve has called “Soft Stop”. With that feature, it slows the max valve speed down to 40% when you are close to the end of the cylinder stroke about to hit the stops, so it doesn’t slam to a halt when you are turned all the way one direction. (That isn’t really a need, but its a cool one to have.) Regarding the steering disengage, the valve I’m looking at is the EHI-40 liter. It is offered with load reaction, which has hydraulic disengage. I wish they would offer the 70 liter valve with this, but for some reason they don’t in open center systems.
So the main hurtle right now is the speed signal that the valve needs. I’m going to look throught the manual and see if it is absolutely necessary for it to operate. I know for the WAS, they have an option for “not WAS” and it simply disables a few of the features that rely on it (like Soft Stop, as well as others)
Not only is speed sensor required, but it wants two sensor sub sytems. Interesting… dont know how to get around that one yet, I’ll start some research.
Yes i do remember that about the two speed sensors. What is the make and model of tractor you are wanting a valve for?
I have used a PVG32 valve with the older PVED-CL valve head and a SASA for some tractors with other brand guidance systems. The PVG32 can be configured with all sorts of parts for all sorts of applications.
I almost don’t want to say what it’s going on because it seems really silly to do this to a tractor this old. It’s a 1978 Allis Chalmers 7580. Its my farms main tractor. I strip till and plant with it. It’s the first tracor I bought by myself, and a couple years ago I have to put all new rubber on it as the old tires were dry rotted. Those two reasons alone are reason enough to never sell the thing. So I guess in the mean time, I’m going to have fun with it. Haha
So the speed sensor issue now seems pretty easy to get by, now that I’ve done some research. Get a multi-sensor to CAN interface module, they run about $100 USD. Take one sensor, mount it up, and create a splice to make two sets of sensor wires. Hook up one set of wires to Sensor Input 1 on the module, then the other set to Sensor Input 2. The CAN interface module will think theres two sensors hooked up and report that to the CAN, which makes the valve happy. At least that seems like how it would work, but I’m sure real life would find issues with my logic.
I have done this for the Valtra T4. Yes, it can be done, but definitely not as easy as plugging in the CAN wires from the AgLeader. You WILL need a steering ECU to handle the speed signals, you also need to have the SASA IID sensor installed, and of course the WAS (that’s not a problem, PVED-CLS can directly read any 5V analog WAS). You need to make sure the CRC signatures on the messages are correct etc.
The pricing on the EHi is what it is, but the availability / delivery times are even worse (guess how I know…). I do have a plug-n-play steering ECU available for this, but it only works if you have a tractor that has CAN bus for the speed signals.
Yeah that’s what I’ve used now for many years with the Danfoss PVEA-CI or PVED-CC valve. Just give the standard aux valve command and that’s it. With PVED-CC you can even do the deadbands and nonlinearity directly on the spool.
So here’s a few things I’ve learned, and also have questions about.
The main differences between the two control valve systems are:
PVED-CLS doesn’t require SASA, as it has the option for hydraulic disengage for autosteer. However, it does require speed input. (I still have questions about the required steering ECU)
PVED-CC / PVEA-CI doesn’t require a speed sensor to operate. However, it does require a SASA to disengage the autosteer. It also requires a modified version of AOG if that’s the system you’re running. (I’m going off of your post back in January, so I’m not sure if something has changed in the recent releases of AOG.)
So it’s sort of a “which one is easier” type decision. The question I still have about the ECU is, why exactly is it required? I guess I was thinking the CLS controller, or even the Ag Leader / AOG controllers, WERE the steering ECU’s… I’ll describe where this question is coming from.
If I go and buy a speed sensor for the CLS style valve, I’ll need to buy a little programable ECU to convert the standard sensor output into CAN messages. The other option is buying a Parker GS100 speed sensor (that’s just for example, I’ll link the user manual below) that is a programable CAN based speed sensor that doesn’t require an additional module to convert over to the CAN. Either choice will give you the option to send out messages on the CAN Bus, and should be configurable to send them in a format that the CLS is looking for.
The main thing with the CLS is, it has to see certain data (like speed) in order for it to be happy and start accepting steering commands from the autosteer controller. Is the steering ECU your talking about the same thing as the programable ECU to convert speed to CAN? I have a felling I still don’t understand exactly how the whole system works. I’m also including the user manual for the CLS Communication Protocol if anyone finds that useful.
First of all, CLS is a full steering controller, PVED series is justa dumb CAN valve. So for the steering curvature commands, it’s the CLS only.
It does have the hydraulic disengage, if you order that specific variant, yes, but then you lose the fast steering capability. You also better do some hydraulics measurements to check that the disengage will work, see the integration manual.
You’re kind of right with the speed over CAN, why you can’t just use the parker sensor directly is because the messages need a certain format that can’t be changed and they need the CRC checksum as well. Also, you need to send the MMI commands to the CLS i.e. which mode to be in, activate autosteer etc. You may find some autosteer controller that supports the CLS directly, otherwise you need the ECU for these.
Ohhh… I didn’t realize fast steering could be slowed down with this option. Fast steering is the whole reason I’m going with a bigger valve like the 40 liter, and they don’t offer it with the 70 liter. So that adds SASA as a requirement to the CLS option. The steering hydraulic system on this tractors is surprisingly good for how old it is. It utilizes a constant flow priority valve behind the gear pump so you’ll always have a consistent flow no matter the engine RPM. The pump itself is a 76 L/min gear pump, but the flow valve regulates the flow to a constant 45-53 L/min (which can be adjusted), and has adjustable standby and relief pressure. The hydraulics should work well, but there’s now other issues I see now that you pointed them out.
Well I’ll be dang, you can’t change the CRC… I looked on the manual, and they let you change a lot, but the CRC is automatically generated (that’s the way it looked to me anyway, I could be wrong.) Then there’s the issue for changing the modes on the valve, like “Road Safe Mode” which would be really good to have. I guess you could go without that, but I’d really like to have it. So now I see, ECU is an absolute must. So to tally up everything you need for the CLS valve:
Steering Wheel Sensor (SASA)
Vehicle Speed Sensor
Mode Switch
Engage Switch (can be included on the Ag Leader system, but maybe not others)
ECU to connect items 2,3,and 4.
I can see why there are easier options. It can be done with someone that knows what they’re doing, but I’m not him…YET. Hahaha
Thanks for all your help and sticking with me @nut. I appreciate it a lot.
Yeah pretty much as you list. Like said, done this before, just have a single rocker switch that has road mode, off-road mode and autosteer on baked into one. Get’s the speed signal from CAN / ISO. The CLS needs to get the double messages with the synced sequence numbers and CRC to stay out of safe mode.
