Where do you get them? I would be interested in them if they work as well as Danfoss.This valve is a third of the price of the Danfoss PVG. Unfortunately there is no way I can afford to use the original.
Where do you get them? I would be interested in them if they work as well as Danfoss.This valve is a third of the price of the Danfoss PVG. Unfortunately there is no way I can afford to use the original.
Oh, good call. Once it was discovered the voltage signal didn't need to provide 10W of power, I thought the thread was done. Didn't realize we still had the issue of converting PWM to analog. I will see if I can find a signal conditioner that does this.Can you confirm (a) you have the 24V version of the valve: not the 12V one and (b) your PWM signal is 12V amplitude: not 5V?
So again I was pretty close LOL.The microchip I'm using is a chipkit Uc32, and changing pwm frequency is a bit complicated
What do you mean the PWM input? And what's this motor controller got to do with it?the PWM input im using is from a motor driver that will run a 12v dc motor up to 25A.
So you need to be able to adjust your output range from [12 to 18V] for testing, down to [6-9V] later for the real deal?I currently have the 24v version because it was the only one that was available, but my end product will be using the 12v version. control range will be 6v-9v.
That's the wrong way to go about it IMO.Im trying to provide all relavant info, but not always sure what is. So from my microcontroller the pwm goes to a dc motor driver that currently drives dc motors. So i want to add the option to drive hydraulic motors instead. So I was planning to be able to wire the motor output into this new circuit to get analogue voltage to control the valve, then just change my pid tunings in software.
My reading of the datasheet says the control range should be 0.25*Udc to 0.75*Udc (unless you actually want only from neutral to one extreme?).neutral is 0.5*udc and control range is 0.5*udc(6v) to 0.75*udc(9v).
That was my impressionyou actually want only from neutral to one extreme?).
I see it as a one-way proportional valve if he isn't using the lower range below neutralThat would be a standard non-proportional two-way valve!
Max.
The reason I am keen to do it this way is so that its very easy to switch to a dc motor if needed, the other reason is that the motor driver has built in opto-coupler, so my 12v and 5v circuits are isolated from each other.That's the wrong way to go about it IMO.
The way it should be done is PWM directly from the micro goes [thru PWM>analog circuit] straight to the valve.
This is correct, Forget about the 24v version, I am only working with the 12v version now.He talking about 2 different valves and it's hard to know which one we're talking about at any given time.
If he says the control range is 6-9v, to me that means between neutral and full flow B, on the valve he's designing for.
Correct, The valve is a two directional proportional valve, but I am only using one direction. 6-9vI see it as a one-way proportional valve if he isn't using the lower range below neutral
I think You are talking about using the the actual motor power PWM output to the valve correct? Not some low power signal?The reason I am keen to do it this way is so that its very easy to switch to a dc motor if needed, the other reason is that the motor driver has built in opto-coupler, so my 12v and 5v circuits are isolated from each other.
I have tried it, all I needed to do was add a 2.3ke pull down resistor to the motor output and it behaves fine. I added the level shifting resistors and the two lc filters and my output looks great.I think You are talking about using the the actual motor power PWM output to the valve correct? Not some low power signal?
If so then your PWM out from the drive is probably not going to behave like you want. It is designed to have a motor connected and probably depends on motor back EMF to adjust duty cycle. With a valve connected it will probably behave erratically or not at all. Have you tried it yet? What is model # of the drive?
It is correct the valve needs no current.I have tried it, all I needed to do was add a 2.3ke pull down resistor to the motor output and it behaves fine. I added the level shifting resistors and the two lc filters and my output looks great.
Am I correct when I say that if the valve needs no current from the signal wire that there is no need for the op amp in the circuit?
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