0-5 V signal

[banderas]

Hi,

I'm trying to build a box that will simulate 0-5V signal.I'm using this signal as a remote temperature set point for a heat exchanger. I have already tried it using DC power supply and potentiometer in series and it works. Now I'm wondering if there is a driver chip that will do same?Thanks

 

[IRstuff]

a driver implies some means of controlling it, so you're asking for a more complex widget. The next simplest thing would be to get a 7805-like 3 terminal regulator and use a switch on the output along with a pulldown resistor to sink the destination.

TTFN

 

[banderas]

Hi,

thanks for replaying to this question. I have already used 7805 to step down voltage from my regulated DC power supply (+-15 V)to 5V and potentiometer in series to change output voltage.I can control temperature by adjusting potentiometer( I believe 40 mV is one C).I'm trying to find some IC's that will do same thing( adjustable 0-5V output). I'm thinking about using buffer op amps.

Thanks.

 

[BrianG]

Hi baderas. From both your first post and the latest, it seems unclear what it is you want to do. Are you looking for manual control or, with your reference to "driver chips", for an interface to a computer?

If you want to produce a computer interface you need to think about the set point control range you want, and how many bits resolution this equals. The simplest starting point is an 8-bit digital to analog converter chip - the well-, inexpensive DAC08 (or variants) - which should give you about 20mV per bit resolution, over a 0-5V total range.

 

[BrianG]

Sorry, typo in last posting. Last sentence should read:

The simplest starting point is an 8-bit digital to analog converter chip - the well-known, inexpensive DAC08 (or variants) - which should give you about 20mV per bit resolution, over a 0-5V total range.

 

[banderas]

Hi,

Sorry for the confusion guys. Let me start all over. I'm building a box that will help me diagnose if my heat exchanger ( here heat exchanger beeing a support equipment for some other tool) communicates with the main tool, before I install it. I'm trying to build a box that will send voltage signal (from 0 to 5 V, temperature range 0-200 C) that is going to simulate main tool and to see if heat exchanger is going to take it. I have already made it to work with before mentioned set up and now I'm looking to improve my design with some IC's and displays.
Thanks.

 

[melone]

Use a micro to control an ADC which sources voltage to the gate of a FET (use the FET as the pot). Also, your micro can output LCD information to drive a simple LCD display.

 

[melone]

Sorry, it should be a DAC, ADC.

 

[banderas]

Melone,

Hi, with "micro" you mean microprocessor? I thought of that originally, but my budget is limited with stock on hand and probably couple more inexpensive chips. I thought of using 68HC11, but those boards are expensive for my application. And I believe HC11 has intergrated 8 bit ADC. would you happen to have some kind of schematic and parts list for your approach? Thanks.

 

[melone]

The HC11 would do the trick. You will need to place plenty of decoupling caps (0.1u and 0.01uF), based on the power pins. You would have to look up a DAC, but that shouldn't be too bad. Otherewise, the FET that you would use would have to depend on the load you are actually driving (purely resistive, inductive, etc.).