4-20mA 12v DC drive

Hi everyone.

im doing a school project making a PLC system regulating temperature in an big fiber switch node.

for simulation im going to run 2 small 12v dc 0,46A fans. 1 fan for simulating the 48V "freecooler" and 1 for simulating an AC compressor for whenever the "freecooler" struggles.

My question. i need an drive that can regulate output from 0-12-15v depending on an input signal of 4-20mA. max current is 0,46A so i want it to be ok for about 1A.

i know this is ok to "DIY" but i don't have the time nor the rescources available.
i need to buy a finish component that i just can plug too a PS and connect fan and my 4-20mA signal from my PLC. also shipping must be within 1 week. ebay is to scary from norway as chineese components are rated with about 1 month shipping time.

Big thanks in advance.

Cato

Normally you would regulate a small DC motor with PWM (pulse width modulation).

Some PLCs actually have a PWM output so no need to use 4-20mA in that case.

Pete.S. said:

Normally you would regulate a small DC motor with PWM (pulse width modulation).

Some PLCs actually have a PWM output so no need to use 4-20mA in that case.

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Yea i know.
But now i need a linear 0-15 or 12V drive that adjusts based on a 4-20mA input.

cateid said:

Yea i know.
But now i need a linear 0-15 or 12V drive that adjusts based on a 4-20mA input.

Click to expand...

What's your budget?

Pete.S. said:

What's your budget?

Click to expand...

i need 2 pieces so no more than 25$ a piece.

At that price point? A cheap Arduino to take the analog signal(convert to 0-5v with a resistor) and output PWM to a mosfet to switch the 12v.
Edit: Because I don't know of any kind of drive that's that inexpensive otherwise

Dravik said:

At that price point? A cheap Arduino to take the analog signal(convert to 0-5v with a resistor) and output PWM to a mosfet to switch the 12v.
Edit: Because I don't know of any kind of drive that's that inexpensive otherwise

Click to expand...

PWM i got on my PLC.

Not what i am asking for.
But thanks anyway

yep arduino would do it for this price and situation very good, i made them to open a valve with pwm at 2Amperes indeed with a simple mosfet (BUZ11)
another way is by using a simple transistor and 2 resistors for current control.
20 mA for 12 Volt means 600 ohm on the base of a NPN to ground, the output will try to keep this 12 Volt, (oke -0.7Volt) so the emitter can direct go the motor.
as it is only for simualtion.

At that pricepoint, the I think the best you might be able to do is get a small relay and switch it on and off. I'd love to be surprised, but I doubt you'll get a Commercial Off The Shelf (finished component) variable speed drive for anything close to that price.

Something like this from Jameco. They have several cheap motor controllers.

http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2159411_-1