Constant 24VDC to Analog DC

What does the 0-10V represent - flow, pressure, level, position, velocity, acceleration?

Control the speed of what?

Please say whether you want to get an output variable from 0 - 10 V or a fixed 10 V from a source of 24 V DC.

Here's a link to a very simple variable voltage regulator circuit, with instructions on how to replace one of the resistors with a potentiometer:http://www.circuit-innovations.co.uk/LM317.html
You'll need to make sure it can handle your power requirements. You can look up the IC specs for that.

If this is a motor with variable load, controlling the voltage may not do what you want.

Hey nag,

I've done something similar but you may need more precision. The real problem is in determining how much current you will need. In my case, I was driving an analog input module with a 0-10 VDC signal. It happened to have a high impedance input so the current requirement was very low. Consequently, the components I chose were very common and fairly small in wattage.

I used a 14K Ohm resistor (½Watt) in series with a 10K Ohm potentiometer. The output was the wiper on the pot. I found that due to the impedance of the analog module, my actual range was more like 0 to 9.7 volts.

To improve on this, you can take advantage of a voltage regulator to start with something closer to 10 volts. The difference will be burned off as heat so it might be a good idea to use a zener diode to drop some of the excess voltage (a cheap trick that isn't current dependant) down before it goes into your regulator. Be mindful of your worst case currents so you won't burn up your components.

It sounds like you have a 24V DC source and want to control a speed input (possibly a variable speed drive) that only accepts 0-10V DC.

What you need is a simple voltage divider circuit to drop the 24V down to 10V and a variable resistance (potentiometer or similar) to then vary this voltage between 0 and 10V.

Voltage dividers

Potentiometers

Additional information may also be available from the manual or application notes of the device whose speed you wish to control.

You still have not answered bigg's question. The 24VDC is just the power source.

If you want a VARIABLE 0-10VDC signal, you need the signal to be representative of SOMETHING that is itself VARIABLE. Like pressure, flow, level, velocity, jelly beans per second, fluxing shunt capacitance, something. If you just want hardware to convert 24VDC to 10VDC, that is just a resistor! If what you want is a TRANSDUCER, then you must fist specify the VARIABLE INPUT to the transducer.

If, on the other hand, you have 24VDC and you want to MANUALLY convert it to a 0-10VDC signal as a speed input to a drive, then what you want is a POTENTIOMETER, which, as I said above, is just a resistor, albeit a VARIABLE RESISTOR. But before you go off half cocked on that, investigate the drive's input choices, many of them allow you to directly connect a Potentiometer of a specific value to an input that is ALREADY providing the 10VDC.

You can use one of these regulators with a suitable heat sink, to get 10 V. Follow it up with a pot.

VOLTAGE REGULATOR 7810 datasheet and application note, data ...

OP neglected to mention a small detail: how much current is desired thru the 0 - 10V output. If it is 10mA, a pot is adequate. If it is 1A, a good regulator on heatsink will be needed. If the desire is a few times 10A, that is an engineering proiect in its own right.