Converting low amperage signal to high current

[TheDingo8MyBaby]

Hello,

I'm doing some prototyping and I'm looking to use a 0-10V signal (10mA max) to control two different proportional solenoid valves.

The first is 0-5V, 0-.37A
the second is 0-24V, .092A

What would be the simpliest way to convert this signal? I'm just looking to do some prototyping so quick and dirty will get the job done.

Thanks in advance.

 

[nbucska]

op.amp with a transistor or power op.amp ( simpler but more expensive)



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Please read FAQ240-1032
My WEB: <

http://geocities.com/nbucska/>

 

[itsmoked]

A dual output bench power supply. Or sometimes two singles are cheaper.

http://www.powersupplydepot.com/listitems.asp?dept=2&main=1

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[IRstuff]

Or even a low-power relay might work.

TTFN

FAQ731-376

 

[TheDingo8MyBaby]

Since this is a proportional valve, I cant use a relay. It opens a certain amount depending on the current I apply.

I'm trying to use a voltage signal to control the valve, I dont see how a power supply would work...unless the power supply could take my signal in volts and convert it to a certain amount of current output.

I was kinda hoping there'd be something off the shelf so I didn't have to go build a breadboard for this.

 

[ScottyUK]

Look for a [blue]programmable power supply[/blue] with an analogue programming input. I know Lambda have one in their Vega range but it has far more power than you need. There are numerous manufacturers of programmable PSU's.


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Sometimes I only open my mouth to swap feet...

 

[Skogsgurra]

Use a dedicated proportional valve driver. That will make your testing less "interesting" - but a lot more useful, since the problems you meet will be real ones and not caused by possible (likely) problem with the basic set-up.

Check these:

http://www.lynch.ca/11-LynchDDPD.htm

or google "proportional valve driver" for many more suppliers.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[MacGyverS2000]

Wouldn't buying a new power supply for prototyping be akin to purchasing a 50-ton Earthmover to fill up your child's sandbox?

nbucska's suggestion is probably the easiest to implement.


Dan - Owner

http://www.Hi-TecDesigns.com

 

[itsmoked]

What say?

http://www.national.com/pf/LM/LM675.html

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[OperaHouse]

You guys still listening to Pease..... Go with PWM. Use a switching regulator chip driving a FET. Convert the 0-10V to 0-100% duty cycle. TL494, SG35XX etc would make quick work of it, Run at 100-200Hz and you even get a built in dither to keep the valve from sticking.

 

[ScottyUK]

Hi Opera & MacGyver,

Those are good ideas but he is [blue]hoping there'd be something off the shelf so I didn't have to go build a breadboard for this[/blue] so most of us were looking at ready-made solutions rather than build from scratch solutions.

Skogs,

Do you know of a supplier of cheap valve drivers? I know plenty of expensive ones! A source of cheaper ones would be useful.


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Sometimes I only open my mouth to swap feet...

 

[Skogsgurra]

No - and yes.

Prop valve drivers are plenty. And they are being used. So, even if they seem expensive, they are the right price. They wouldn't sell if they weren't.

The OP said that he wanted OTS gear. A dedivated driver is as close as you can get - it IS OTS.

Remember, this is Eng-Tips. Questions asked are supposedly about engineering - not kitchen table experiments.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[ScottyUK]

They're definitely used - big industrial facilities like us aren't geared up for doing circuit development and assembly, so we just bear the cost of the ready-made units. To us £100 for a driver is trivial in the cost of a typical control valve installation, but it's a lot of money for a kitchen table experiment. But you're right, kitchen table experiments are not what we should be supporting.


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Sometimes I only open my mouth to swap feet...

 

[Skogsgurra]

...which doesn't mean I don't do it myself from time to time...

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[OperaHouse]

Get an older HP power supply on ebay. If I can remember correctly, a HP 6253 is a dual 40V power supply (said you had two solenoids) with a terminal strip on the back that lets you do just about anything with voltage and current. The factory manual is available for download at agilent.com with all the info. With shipping you should be able to pick one of these up for less than $75.

 

[TheDingo8MyBaby]

Thanks guys!

The proportional solenoid driver is exactly what I was looking for. Had no idea they existed...so I'm glad I asked.

I would run a power supply, but space is limited around the lab so I'd prefer something small and compact like the prop solenoid driver.

 

[itsmoked]

OperaHouse BTW I do like your PWM. It is the way to go in any product.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[ScottyUK]

Have a look at

http://www.axiomatic.com/remote-solenoid-4-20ma.html

for an example. I haven't used this company but it looks quite a flexible little module.


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Sometimes I only open my mouth to swap feet...