Hello,
Do you guys know anything like variable voltage digital io.
Normally using a dio card gives an output 5v Or 0.. I will need all sorts of voltage 5v-24v.
Seen something like that?

Thanks
Jis

 

There are a number of ways of achieving this. You need to tell us more of what you are attempting to do.

On way is to get a DAC (digital-to-analog converter) board.

 

Thanks for reply..I am interested in generating finite number of digital output for a test equipment. Its easy to buy this from market. But I do get this only for digital voltage range. But I need voltage range 5 to 24v.
I should also be able to control individual output voltage..

 

Hundreds of commercial boards are available or you can build your own. Google DAC board. How much current do you need to supply?

 

The current will be max of 20ma per channel

 

There is a kind of universal IO port, call iC-JX which has independen driver supply of 12-24V with read back function, as well as 10 bit analog input on each of the 16 port. Board example: http://www.raspberrypi.org/forums/viewtopic.php?t=9556&sid=a98d84943f7db20dd53348135d463765 and more on interfacing to industrial voltage: http://ichaus.biz/wp1_mcu_interface .

 

The conventional approach to digital is that you have two values, On and Off. You can represent these two values in many ways, one example is that Off is 0 volts, On is 5 volts.

The fact that you want more than two values tells me that you don't want digital.

What you want is digital CONTROL. This is very normal. Normal people use Digital to Analog Converter (DAC) to accomplish this task.

 

What I meant by "variable" is my digital ON can be 3V,5V,12V,13V,15V or even 24V.

Individually controlling mean , one digital output can be 0, other one can be 3V, third one can be 15V etc.

thanks
jis

 

What I meant by "variable" is my digital ON can be 3V,5V,12V,13V,15V or even 24V.

Individually controlling mean , one digital output can be 0, other one can be 3V, third one can be 15V etc.

thanks
jis

That is what DAC does.

 

why not use a proper voltage rated open colletor output buffer? then all you need to do is feed the voltage you want to make the 1's to the pull up resistors.

 

The output of your DAC card adding a LM358 to amplifing the voltage from 0~5V to 0~30V, and the gain set to 6.

If you afraid of the current od op amp is not enough, then you can adding a bjt to amplifying the current.