Debating POSITION CONTROL. What is it to YOU?

   / Debating POSITION CONTROL. What is it to YOU? #1  

Singalo

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First let me lay out the most common theories of what position control is that I have run into most frequently.

Theory #1: Position Control is nothing more or less then the ability to stop the 3pt hitch at any point in the length of it's travel. For the sake of this discussion this will be referred to T#1

Theory #2: Position Control is the mechanism or scheme by which the 3pt hitch can be set to a predetermined height repeatedly with out the need to make fine adjustment. Think, set it and forget it. For the sake of this discussion this will be referred to as T#2

Theory #3: Position Control is a "Self Regulating Circuit", that automatically adjusts the height of the 3pt hitch. This automatic adjustment is needed in order to correct "Drift", that is the droop of an implement, that occurs due normal and acceptable leakage. For the sake of this discussion this will be referred to as T#3


I hope we can all agree that these three theories are expressing completely different ideas, and are mutually exclusive.

This topic has been discussed in several diffident threads. But to me, it always seems that there are folks that weigh in that feel that they are absolutely correct in their understanding of what Position Control is. This is not a criticism. I say this only to illustrate the problem it creates for folks that don't yet understand. If I, as a representative of the group that "Does not Know", accepts the certainty of Authority #1 that T#1 is correct. Then what am I to make of Authority #2 and #3 who are equally as certain that T#2 and T#3 are correct. From my perspective, and although I respect the experience of each of these authorities upfront, I can't reconcile the Fact, that all 3 theories can not be simultaneously correct. So although Authority #1,2 and 3 are "Certain", I am not.

Id like to respond to some comments made in another thread that sparked me to create this one.


Bullitt said:

With position control with the tractor running and 3PH lever left in one place the 3PH will not drift down.

The question is, what do you mean by "Position Control". If, by position control, you mean T#1. Then That is saying one thing.

IF however, when you say "Position Control", you are speaking about T#3, then that is saying something totally different.

So, I take this:
With a neutral lift after hours with a heavy load you may notice some leakage but very very very minimal if everything is working properly.

To mean that you consider "Position Control" as something that is Void of this "Self Regulating Circuit". Or at the very least, does not require such a circuit to be considered position control.

Further, I take this quote from Grandad:

+1 What he said. Any tractor, regardless of what type of lift control the 3 pt has, should not "drift" down so you have to re-adjust it all the time. If it's doing that, there is something worn or leaking in the hydraulics.

To be supporting testimony.

If I am understanding both of you (Correctly), Bullitt and Grandad4, then there are a few things that can be taken away from this.

1) Pretty much all modern tractors have the ability to stop the 3pt hitch at any point in the full length of it's travel, thus pretty much all modern tractors have "Position Control". I try not to speak in absolutes, so that's why I say "Pretty Much".

2) Drift, or the process of drooping due to "Acceptable Leakage", is normal, but in a properly working system should be very slow, on the order of days at least to have any noticeable or significant movement, which essentially means in practical terms, there is no need for a "Self Regulating Circuit". Because any operation you may be doing, be it raking, tilling and so on, will not be done on a time scale where "Normal Drift" will have any appreciable affect on that operation.

That said, I feel that at least Grandad4 and Bullitt are proponents of T#1. I too feel, or at least felt at one time, that this was an accurate description of PC. Now, I simply can't be certain. and the reason why is this. I have heard supporting testimony from a fair selection of people that "SHOULD" understand the true nature of PC. Dealers and Brand Representatives that subscribe to one or a combination of the 3 theories listed above. The only certainty that I have is that they are NOT all on the same page.

I am not here to personally prove what the true nature of PC is. But I would like to see a constructive conversation from the various proponents of the differing theories above. Depending on what you choose to accept as factual, I have heard convincing explanations for at least two of the theories listed above.
 
   / Debating POSITION CONTROL. What is it to YOU?
  • Thread Starter
#2  
As a follow up, I'd like to point out that part of the argument between theories hinges on ones notion of how fast "Normal Drift" occurs.

Proponents of T#1 believe that "Normal Drift" happens over a long period of time, such that during normal operation, this drift does not have, or should not have any appreciable affect on the operation. If it does, this means there is a problem with the hydraulics. Meaning that there is considerably more leakage then would otherwise consider to be normal or acceptable.

Proponents of T#3 believe that "Normal Drift" happens over a much shorter period of time, such that during normal operation, this drift can and will affect on the height adjustment of the 3pt hitch, which in turn requires those without PC to make frequent manual adjustments during normal operation. PC is intended to deal with this drift by automatically adjusting for it. Few of the dealers I spoke to share this idea. Still other dealers claim T#2 is all PC is.
 
   / Debating POSITION CONTROL. What is it to YOU? #3  
I chose T-3
 
   / Debating POSITION CONTROL. What is it to YOU? #4  
Having recently rebuilt the hydraulics on my MF-135 tractor as part of a complete restoration project, I fully comprehend how position control works. However, I prefer to look at it like this...

A: I pull the little lever back and the implement goes up.
B: I push the little lever forward and the implement goes down.
C: I stop moving the little lever and the implement stops too.
 
   / Debating POSITION CONTROL. What is it to YOU? #5  
This is your basic definition.

It enables your three-point hitch to stay at the height you set.

How different tractor achieves this is the real question.
 
   / Debating POSITION CONTROL. What is it to YOU?
  • Thread Starter
#6  
Having recently rebuilt the hydraulics on my MF-135 tractor as part of a complete restoration project, I fully comprehend how position control works. However, I prefer to look at it like this...

A: I pull the little lever back and the implement goes up.
B: I push the little lever forward and the implement goes down.
C: I stop moving the little lever and the implement stops too.

I don't know about anyone else, but this sounds pretty much like T#1 to me.
 
   / Debating POSITION CONTROL. What is it to YOU?
  • Thread Starter
#7  
This is your basic definition.

It enables your three-point hitch to stay at the height you set.

How different tractor achieves this is the real question.

So are you saying that Position Control actually has no one set definition?
 
   / Debating POSITION CONTROL. What is it to YOU? #8  
Ideally you want position control and Draft Control. Most all tractors have position control. How well they work is taken in by the three T's that you described. If they aren't T3 then they really aren't position control because if it drops for ANY reason and doesn't auto-correct, then it is not position control.
Then you add in draft control to the position and you have a workable 3 PH implement. Lets say you are pulling a plow of some sorts that is set by position control at 6" depth which is about all your tractor can handle in the normal soil conditions. You encounter heavy clay soils at some point that loads the tractor heavier. With draft control, it would sense this excess load and automatically raise the implement so you regained traction or speed as the case may be. This has to be set as you are doing the operation but once set it automatically raises when excess load is encounter and then lowers the implement back to preset height of the position control lever when the load is normalized.
I would say that T1 isn't position control if it doesn't compensate for drift.
I don't see a distinction between T2 and T3 as it seems both are the same "set and forget"
 
   / Debating POSITION CONTROL. What is it to YOU? #9  
I just looked at all the LS models and none of the smaller tractors have draft control until you get to the Rxxxx series, Then they all seem to have it. The J series and G series only have position control and since I have never been in the seat of one that small, I couldn't begin to say how well they work. As far as that goes, I cant tell you how well my Kubota B26 position control works either as I have never used a 3 PH implement on it, maybe never will but I can tell you that it doesn't have draft control as it only has one lever to control the 3 point linkage (draft control would have 2).
 
   / Debating POSITION CONTROL. What is it to YOU? #10  
I don't know about anyone else, but this sounds pretty much like T#1 to me.

Actually, it's a combination of all three, and then some. I could get technical, very technical, but I'm tired and simply don't feel like it at the moment. However, I will say this... The entire system is a marvel of engineering that seems very complicated at first glance, but once you understand how it all works it's actually very simple.
 
 
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