I had thought to use a digital potentiometer (e.g. AD5206 with 6 channells), to control the potentiometer with arduino, use an external supply (many industrial devices have a 10V external supply) to the terminal of the potentiometer and connect the pot wipe to the device input.
But alas I've realized that for the AD5206 (and many other digital pot) it is not possible to use external supply to terminals of the pot greater than the power supply of the IC.
So I could smooth a 0-5V signal at least with this kind of technology.
So I'm wondering how can I use this 0-5V signal to drive something (a op amp?) supplied with 0-10V in order to control a devices accepting 0-10V input.
I have forgotten much of electronic
So I hope someone of you can help me! THANKS!
all help is very appreciate...
r.
PS: I have some op amp TL082, ua741... so if it is possible to use one of this is great!
Take the PWM output and put it to a transistor whose collector goes (through a resistor) to 10V. This will give you a 10V PWM signal. Then smooth that with a filter to give you the control. http://www.thebox.myzen.co.uk/Tutorial/PWM.html
Thanks, could be good... but alas I need to control about five-six devices. For this reason I've thought to use AD5206 with 6 channel. Or to use other digital pot, but I2C, in order to use many of them with two wires
But about your solution, I can perform a fine control? Because I need, for example, to drive an inverter and to perform 0.4V+-0.1 step.
Thanks for your help
r.
PS: I cannot permit ripple, cause the input of one device is 10bit converted and it is very sensible. I'm also considering to open this device and see if I can control directly the 10bit
Ripple is inevitable with what ever method of control you have, it's just the amount that you can tolerate that is an issue.
The AD5206 is an SPI device so you can chain as many as you want together without having to go to I2C. As it will only cover 5V then you do need an op amp to convert this into your control voltage. Given that you are probably better off using a D/A chip.
Yes, I think a little of ripple is inevitable and a good capacitor could reduce it.
Uhm... so SPI is like a BUS protocol? Sorry for my ignorance But I didn't figured out how to use like a bus.. cause for example I don't know how can I set address.
Please, could you explain me a circuit on how to use an op amp to convert 0-5 from pot to 0-10... thanks!!!
A D/A could be a useful solution, I hope also cheap. Could someone tell me good and cheap D/A (accepting I2C or other compatible wire protocols)?
cause for example I don't know how can I set address.
Most SPI devices don't have and address (although some have) you use the chip enable pin to select what device you want to talk to. http://www.arduino.cc/playground/Code/Spi
Please, could you explain me a circuit on how to use an op amp to convert 0-5 from pot to 0-10.
Make R1 and R2 the same for a gain of 2. Feed the power from 10V external.
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The solution with op amp works well. I just performed a circuit with AD5206 and ua741. For resistors of op amp I've chosen two resistors 330KOhm high precision that I've found in my component box.
There is only one little problem, op amp needs about 11V to carry out 10.00V... so I think I'll need to use an additional 12V supplier, but it is not a problem. I've found an old switch supplier taken from a fax with 5V and 12V outs
as soon ass I'll accomplish the final circuit I'll post the complete schema.
so I think I'll need to use an additional 12V supplier,
yes that is what deSilva was on about. If you get an op amp capable of rail to rail operation you won't need the extra voltage but these are more expensive than a 741.
yes that is what deSilva was on about. If you get an op amp capable of rail to rail operation you won't need the extra voltage but these are more expensive than a 741.
ah, ok... now I understood what means "rail to rail" op amp
for the first implementation and testing I think I can work with external supplier...
But I didn't figured out how to use like a bus.. cause for example I don't know how can I set address.