This is not about compensation! Valves with which they give a constant flow which does not matter here because the flow needed is different depending on the demand of proportional valves at a given moment.
We need a constant pressure and basically its constant difference in levels at the input and output. I use such a layered valve for cetopes:
Thanks to it, we have a constant pressure difference between the input and output of the proportional valve, regardless of the pressure difference at P and the resistance of the steering.
I can take it from you if you don’t use it anymore Darren. I have open centre so the drain should be good for me. Can use the drain to go back to other functions.
Was going to say, if anyone wants that valve, it would be ideal for open center systems, as the drain can either be drained, or used for second function… Happy to let it go for much less than I paid if you can cover postage also, send me a message if you like.
I also have lots of fittings etc so if you need anything with it let me know.
Returning to the topic of the LS line, wouldn’t it actually be sufficient to just put a 0.3-0.5 mm orifice to the autosteer valve LS line, then one could use any valve without bleed to tank? It should only bleed something like couple of litres per minute back to tank at full pressure.
I’m continuing as a monologue Seems like Covid-19 has infected everyone manufacturing cartridge valves, hence I went for a second alternative, bit more costly but should be quite a neat package. Danfoss PVG16 valve body with the PVHC control, i.e. just two coils driving the pilot hydraulics directly hooked up to the Cytron. The spool is 10 l/min max. flow with the LS line discharged to the T line in neutral. There’s also an integrated shuttle valve in the LS line, so should be able to hook up the whole block with no additional valves, just an adjustable pressure switch to the orbitrol LS line and manual shut-off valves to A/B lines for safety.
Hopefully getting the bits already this week and can start hooking up.
I had to play with the settings a bit
Proportionnal gain 5
Ouput gain 26
Minimum PWM Drive 40
It works well! (on a Valtra 8050 Hitech) With AOG v4.1.12 and cytron
I will probably test with v4.2.02
I will see in the mid of summer if a SP10-57C also work.
What value did you end up using for the pressure relief in the LS line? The orbitrol seems to have 140 bar in the LS line.
Are you switching the autosteer off with a pressure switch, and if so, what pressure value roughly you have for the kickoff?
Picking my PVG16 tomorrow, just then the WAS missing from the setup. Where did you put the valve package itself, under the cab floor where the priority valve and hydraulic filter sit seems like a good spot?
Hi for the relief valve I set it at 1400 psi (100 bar?) it’s enough to steer without front duals, the pressure is between 200 and 1100 psi in motion.
I have a pressure switch on orbitrol LS set at 230 psi (16 bar).It’s on a 12v circuit similar to the PTO circuit of Valtra (My Old 8150 Mega)
It work good but sometime it stops just after starting. Probably because the shuttle is not moving fast enough. It happen when autosteer start with a large correction.
I moved the batteries on my Valtras under the cab next to the filter(not enough power in the winter and to hot in the summer!) So I have a nice spot in the engine compartment!
I’m now bit hesitant with what my hydraulics guy got me, started thinking driving back from the dealer So I got the Danfoss kit now on table, but with open center pump plate. However, I feel this should work since the LS line is going through the Danfoss valve. See below:
So the LS line from the orbitrol comes in from below, through the integrated shuttle valve. Whenever one of the valves (autosteer or orbitrol) is operated, the LS line is pressurised, hence the flow diverter in the Danfoss valve should move with the LS pressure and hence the flow to tank should be stopped. There’s a check valve in the orbitrol on the P line so that shouldn’t depressurise through the open tank connection. LS from the Danfoss valve goes to the priority valve and the T/P/A/B connections are tee’d together.
Thoughts? Or should I go for the closed center version directly, which looks like this:
Edit: Looking at the service manual, it’s just one plug changed to an orifice that makes the difference between OC and CC valve, so should be a small thing to change.
Maybe the closed center version is better, you will still have a relief valve on the P instead the Ls.The downside is that all the oil will go though the valve instead the others functions when the valve hits the end?
I have set the max steer 5 degrees less than the real max so it give some room for the valve when overshooting.
If you go with the open center is it a chance that you can lose pressure when steering manually? Thats a bad thing!
On the relief valve on the right side does it read the difference between the spring side and the arrow side? Or is it set to an absolute value?
Edit: It is possible to block/plug/rise the pressure setting of this valve? Then the open center version will work great. But maybe it’s a bad idea to tweak this kind of stuff!
Glad the hear that you can swap with just on plug!
The problem was solved - the valve is actually the closed center version! They had just had the open center in stock and modified it with the plug - hence the wrong part number on the valve body😀
We discussed also about the pressure relief and thought that it’s OK with the regulator on the P line. So the only thing needed except the valve is the pressure switch to the LS port.
Seems like Covid-19 has infected everyone manufacturing cartridge valves, hence I went for a second alternative, bit more costly but should be quite a neat package. Danfoss PVG16 valve body with the PVHC control, i.e. just two coils driving the pilot hydraulics directly hooked up to the Cytron. The spool is 10 l/min max. flow with the LS line discharged to the T line in neutral. There’s also an integrated shuttle valve in the LS line, so should be able to hook up the whole block with no additional valves, just an adjustable pressure switch to the orbitrol LS line and manual shut-off valves to A/B lines for safety.
So I got the Danfoss kit now on table, but with open center pump plate. However, I feel this should work since the LS line is going through the Danfoss valve. See below: