Logic for scaling more than two coordinates required

[manmeetvirdi]

There are only three points ( knowns ) so the equation can have only three unknowns.
.

Is this a Theorem?

 

[Peter Nachtwey]

I wasn't quite right

Is this a Theorem?

There needs to be at least as many knowns ( points ) as unknowns ( coefficients)

Below a certain value, follow one slope and above it follow another. My German friends call this a Knee-curve.

If they are the same people I am thinking about then I thought the called it a nic. It is trouble because it formula is not documented. This leaves it to the customers to guess and they will have the same problem that the OP has.

Non linear stuff is a tech support nightmare as we can see.

 

[ndzied1]

If they are the same people I am thinking about then I thought the called it a nic. It is trouble because it formula is not documented. This leaves it to the customers to guess and they will have the same problem that the OP has.

Non linear stuff is a tech support nightmare as we can see.

When they talk about flow characteristics they usually call it a "knick" spool. When they talk about gain curves they usually call it a knee curve or an inflected curve.

All of these spools were developed before the fancy electronic circuits and fpga's that make modern high speed digital controls possible. They were trying to do hydraulically what was then impossible electrically. I would argue that they did a pretty good job for the technology available to them.

The good news is that your message is getting out. In one of the recent news letters they put out, they said that due to increased customer requests, they are coming out with more linear characteristic spools for the valves.

 

[Peter Nachtwey]

It isn't happening fast enough

The good news is that your message is getting out. In one of the recent news letters they put out, they said that due to increased customer requests, they are coming out with more linear characteristic spools for the valves.

I know, I have talked to a few senior people at BR.

You don't know how much pressure I have got from our marketing people to put valve linearization into our controller and I have refused. If BR can linearize a valve then we must be able to do it too. The problem is that non-linear valves messes up the auto tuning and a simple linearization table can't fix it. The linearization tables linear the velocity or gain but not the frequency response.

 

[hajdeen82]

Hello
Sorry i wasn't online for a couple of days. I thank for all the replies. i was trying to say something like what mr.ndzied1 has mentioned as knee curve. I have used to simple linear scaling and changing between the two slopes finally.
Thankyou all guys onceagain