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1  Using Arduino / Programming Questions / Re: More than one OR statement? on: January 21, 2013, 12:22:40 pm
Ah thats where I was going wrong.  I too was only using one '=' not two

Thanks for your help  smiley
2  Using Arduino / Programming Questions / More than one OR statement? on: January 21, 2013, 12:13:47 pm
How do I add more than one OR statement?

I currently have;
Code:
if(dT > 0.2 || dT < -0.2) {

how do I add another OR statement to it?

I want to add x=360
3  Using Arduino / Project Guidance / Re: Driving a 0-10vDC signal control valve on: November 12, 2012, 01:22:48 pm
You can create gain by inserting a resistor between the two 100k resistors and the output.

So if I put a 100k resistor in where you said that would give me a gain of 2.

What does the 100k resistor thats currently located between the output and ground?

I know the circuit I found does not allow for any conditioning of the PWM.  I assume I will need some sort of low pass filter on the op-amp input.
4  Using Arduino / Project Guidance / Re: Driving a 0-10vDC signal control valve on: November 12, 2012, 10:41:28 am
I found this circuit which is a 0-10v output. I'm pretty sure the triangle is an op-amp (LM358M) but what are the transistors doing?
You don't like the circuit that I referenced?

Oh no, not that... I have an old HVAC controller and found the circuit in some of the documentation so I was trying to understand what was going on.
5  Using Arduino / Project Guidance / Re: Driving a 0-10vDC signal control valve on: November 12, 2012, 10:39:26 am
One to buffer the output and another to limit its current.

That circuit requires a 0-10v input.


So the transistor with the collector connected to the 24v is to isolate the input signal from the output and the other one is to limit the current.

Maybe I was wrong about the triangle being the op-amp.... Might be more to it than that.

I'm sure you are right about it needing a 0-10v input but can you explain.
6  Using Arduino / Project Guidance / Re: Driving a 0-10vDC signal control valve on: November 12, 2012, 09:36:18 am
I found this circuit which is a 0-10v output.


I'm pretty sure the triangle is an op-amp (LM358M) but what are the transistors doing?
7  Using Arduino / Project Guidance / Re: Driving a 0-10vDC signal control valve on: November 03, 2012, 05:00:49 am
So I could use something like this?

http://uk.rs-online.com/web/p/general-purpose-dacs/0402881/
8  Using Arduino / Project Guidance / Re: Driving a 0-10vDC signal control valve on: October 31, 2012, 09:34:02 am
I think I may have left a vital piece of information out.

The valve is 24vAC powered.  The 0-10v is just a signal, I don't think the current draw is very high...

The 0-10v input expects to see a DC input not a DC PWM.  So I can't just give it a 0-10v PWM signal.
9  Using Arduino / Project Guidance / Re: Driving a 0-10vDC signal control valve on: October 30, 2012, 11:48:33 am
Had a bit more of a search using a variety of terms, unfortunately the search function doesn't like the term '0-10v'.

Is this the kind of thing most people are using?
http://ruggedcircuits.com/html/circuit__20.html
10  Using Arduino / Project Guidance / Driving a 0-10vDC signal control valve on: October 29, 2012, 09:29:54 am
I have a control valve actuator that accepts a 0-10vDC control signal to dictate the position of the valve.

Is there a circuit that someone has used to do this to drive it from an Arduino PWM?

I assume the 0-5v PWM needs to be turned into an analog signal and then boosted to 0-10v.

Can someone point me in the right direction.
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