so the valves are pvg 32 but they are a bit old, so were gonna have to clean them up a litlle but they should work. does the valves need any sort of failsafe like a shock valve or presure relief valve in case something goes wrong or should it be fine.
since opengradeX is controling the valves, how about a way to manually control the implement? a switch or something like that, so that you wouldn’t have to plug a tablet to it just so you could move it?
The PVG I sourced had an internal pressure reliefs that bypassed oil if the valve is closed and tractor is still supplying. You would have to find out if your valves hasthat. I haven’t had a chance to finish the 12V portion yet. I believe I can do it with and op amp and a couple resistors. I can also add some pin outs on the V2 boards for some buttons if you would like to add them later. I probably won’t spend much time coding it in though as I will mostly use it on a CNH system and have the levered in tractor to lift and lower imp. As well the Grade control Module sits in a sealed case that’s not very easy to get apart once assembled so it may just be easier to grab the tablet if you need to move it
hmm, i know you can add a presure relief to the pvg block but what your talking about sounds more like an open centre where it just circulates the oil from the pressure input to the tank output.
as for the buttons i can see your point with having them in the box and not being able to control the from the cab anyway… may be something for bench testing but other than that i see what you mean
@blackace “The PVG I sourced had an internal pressure reliefs that bypassed oil if the valve is closed and tractor is still supplying. You would have to find.”
So it must be a canbus valve, since you can’t add a potentiometer to control it. But then it must be possible to have a switch between the controller and a potentiometer output, to control output from the PCB
The one I looked at was an anolog input, but where as the CNH and Deere looke for 0-5V, that valve looks for 0-12V. All that needs to be done is too convert the 5 V signal to a 12 V signal and add 12 v regulator to keep it at a constant 12V instead of whatever the tractor is at (13+V when running).
I know there are 105 posts here, but they cover your needs:
hmm, correct me if i’m wrong but are the valves used for the autosteere not proportional valves? think we settled on a on/off system since its only a grader and i dont think the software is able to give out precise volts in order to use a proportional valve. since we have a LOT of Danfoss pvg stuff at home we decided if it moves to fast or to slow we will just change the glider within to make a larger or smaller output to the cyllinders
That doesn’t help my cause because I wrote all the firmware for the two Module basically from scratch. I only need help with the electrical side of it.
No this is a proportional system it uses a 12 Bit DAC so should be plenty accurate enough to control a prop valve. There is also a PID system running on the grade control that comes up with the analog values and sends them to the DAC’s
ohh my bad then, but that’s okay we have quite a few proportional electric aktuators. so the grade module sends out the recuired volts for the valves? since there needs to be a constant 6V on the spool for it to be in a neutral position and then it goes either lower or higher depending on wich way it’s supposed to go? sorry if im not following along
In the post about cytron are at least 2 ways to convert 5v to control the Danfoss. Or even a pot between 2 1000 ohm resistors (12 v, output to signal and gnd, )
@Bjarke_Kristensen I may make a bit of a diagram today, that will kinda explain how the system works and communicates. May help other to understand how it works and help with questions.
@Larsvest I kinda read through it but didn’t find anything about 5 v signal conversion but I must have missed it. Will re read when I get a have a bit of time.
thanks, that might clear a thing or two up 
Look for posts after 28 here .ino for PCB+MD13S+Danfoss valve - #29 by grabik
Look at the specs for this item, and the alternatives they list at bottom. https://m.nl.aliexpress.com/item/33021792064.html?gatewayAdapt=gloPc2nldMsite&spm=a2g0o.productlist.0.0.1788645fqzeplk&algo_pvid=35b65782-a153-4231-9e87-6be279f14fa0&algo_expid=35b65782-a153-4231-9e87-6be279f14fa0-0&btsid=a915c4d7-f978-4973-82da-aa892c7499bd&ws_ab_test=searchweb0_0,searchweb201602_8,searchweb201603_53
@Larsvest I’m not sure that will work in my situation for two reasons
-------------------------------------------------------OPENGRADEX---------------------------------------------------
-SENDS —DATA— Cut Delta, Cut Dir, and AutoStaste to GCM
-SENDS —SETTINGS— PGAin, IGain, DGain, Valve Type, Ret Deadband, Ext deadband to GCM
-RECIEVES —DATA— Auto State, Valve 1 Voltage, Valve 2 Voltage from GCM
-RECIEVES —SYSTEM— Firmware Version from GCM
-RECIEVES —GPS— NMEA to from AM
-RECIEVES —IMU— Roll, Pitch, Yaw to from AM
-RECIEVES —SYSTEM— Firmware Version from AM
-RECIEVES —SYSTEM— Firmware Version from AM
-Run OpenGradeX
-Host UDP Server
-Get Remote Commands from Handheld remote
---------------------------------------------------ANTENNA MODULE------------------------------------------------
-SENDS —GPS— NMEA to OGX
-SENDS —IMU— Roll, Pitch, Yaw to OGX
-SENDS —SYSTEM— Firmware Version to OGX
-SENDS —WIFI— Scans for available networks to OGX
-Transfers IMU/GPS data to OGX tablet in tractor
-Hosts OGX Network
--------------------------------------------GRADE CONTROL MODULE---------------------------------------------
-RECIEVES —DATA— Cut Delta, Cut Dir, and AutoState from OGX
-RECIEVES —SETTINGS— PGAin, IGain, DGain, Valve Type, Ret Deadband, Ext deadband from OGX
-SENDS —DATA— Auto State, Valve 1 Voltage, Valve 2 Voltage to OGX
-SENDS —SYSTEM— Firmware Version to OGX
-The Grade control Module receives the cut delta and Cut Dir from OGX via the wireless UDP network. It then uses that value in a PID loop and maps that value
to a set voltage range.
-CNH and Deere
0V<<<<<<<<<<<<<2.5V>>>>>>>>>>>>5V
Max<< Retract±-----------------+Extend>>Max
-For Danfoss
0V<<<<<<<<<<<<<6V>>>>>>>>>>>>12V
Max<< Retract±-----------------+Extend>>Max
-Wirelessly connects to OGX Antenna Module
Lucky you with Danfoss stuff at hand. To control without computer/tablet a dc dc converter can do. One like this might be good, it has box and you can see if you get too close to the Danfoss fault limits at about 2 and 10 v. CNC DC DC Buck Boost Converter CC CV 0.5-30V 4A Step Up Down Adjustable Regulated Power Supply Module for Solar Battery Charging | Alexnld.com
Probably better so set between 2 and 10 V , as Danfoss technic data say:
Input signal monitoring: The input signal voltage is continuously monitored. The legal range is between 15% and 85% of the supply voltage. Outside the range and this section will switch into an active error state.
[quote=“Larsvest, post:52, topic:8313”]
The legal range is between 15% and 85% of the supply voltage. Outside the range and this section will switch into an active error state.
IMG_0001.pdf (64.7 KB)
Yes you are correct. Sort of. It is actually between 25% and 75%. As you can see in the above document . I just used 12V for simplicity. CNH and Deere are the same if it get below .5 volts or above 4.5(10%-90%) it creates an error, when you select a valve type from within OGX it sets all Mins and maxes in On the grade control module. So it will not create any errors
If it’s canbus, it’s dead easy as Danfoss uses standard isobus codes.
As for PVG, there’s a relief valve in the main module, different versions for closed and open center. The difference is basically a plug, check out PVG service manual. All PVEA series are compatible with one another and use 13 bar pilot pressure, so if you convert a manual-only PVG to electrohydraulic, check that you have the pilot pressure reduction valve in the valve group. PVHC actuator uses a higher pilot pressure, don’t go for that as it’s same price as PVEA and just crappier, no feedback etc. You can also use a canbus actuator like PVEA-CI (which is the same price as analogue ones) and ditch all the Cytrons etc and just use a canbus module on the PCB. For me, this is by far the easiest way to work with PVGs.
All the technical manuals are available on Danfoss website. With PVG32 body you get higher flows and some more exotic options, PVG16 is maybe bit better price point if you’re buying new and still goes up to 80 l/min flow.
