How to use switching power supply :-)

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How to use switching power supply :-)

Postby rastoboy » Thu Apr 20, 2017 7:42 pm

Hello,

I'm very much a novice to Arduino and creating circuits. I read that if I want to use multiple servos (and I do), it's a good idea to get an external power supply. I ordered this Meanwell 5VDC, 20A power supply :

https://www.sparkfun.com/products/14098

because I (probably naively) figured a 5v power supply would be right for my needs. I figured I'm using the same hardware I used the 5v power from Arduino drive, so I needed a 5v power supply. So that's kinda one question right there :-)

But the big question is: how the heck do I use this thing? I rather expected it to have a plug that would plug into the wall like a computer power supply. Googling has shown me datasheets for it and such, but frankly it's over my head. I can't seem to find any basic "how-to" guides to this sort of thing. Anyone know of a guide somewhere I could study to learn more?

Any input would be greatly appreciated! :D

Best,
lee
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Re: How to use switching power supply :-)

Postby jremington » Thu Apr 20, 2017 7:55 pm

Download the data sheet from the web site. The last page has a diagram showing which screw terminals are to be connected to what. Note that 20 amperes is enough for about 20 standard servos, all running at once.

ACL = terminal 1 = AC line (black), use a standard 3 prong AC plug with ground
ACN = terminal 2 = AC neutral (white)
FG = terminal 3 = frame ground (AC green).

V+ = terminals 6 and 7 = +5V
V- = terminals 4 and 5 = 0V

connect.gif
connect.gif (11.22 KiB) Viewed 455 times
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Re: How to use switching power supply :-)

Postby n1ist » Fri Apr 21, 2017 4:31 am

Make sure you put an insulating cover over the screw terminals for safety. They seem to attract wayward bits of conductive schmutz from your bench...

/mike
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Re: How to use switching power supply :-)

Postby rastoboy » Fri Apr 21, 2017 2:53 pm

Thanks, y'all. Can I ask some more stupid questions?

Could I trouble someone to link me to an example of the kind of AC plug in question? Because I've never noticed one with those wires...or I suppose they're normally hidden?

Also, so it sounds like I use terminals 6 and 7 like the "5v" connectors on my Arduino Uno board? But I'm not sure what the 0V terminals 4 and 5 are for.
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Re: How to use switching power supply :-)

Postby Valen » Fri Apr 21, 2017 3:34 pm

0V(olt) is the same as GND (ground) on the arduino, or minus like of a battery. It's the other end of the loop. You always need to connect at least 2 wires to make a circuit.

I'm pretty sure jremington means this kind of cable. Or similar one with whatever fits into your country's wallsocket.
https://www.sparkfun.com/products/11299

The powersupply doesn't have a socket for the opposite (trapezoid) connector C13, so you would have to cut-off that end and attach the bare wires in the mentioned connector pins 1,2,3.
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Re: How to use switching power supply :-)

Postby rastoboy » Fri Apr 21, 2017 4:00 pm

Ok, ok. Starting to (maybe) make sense now, thanks.

So here's a weird question--when do you attach to 0V and when to ground? How are they different?
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Re: How to use switching power supply :-)

Postby rastoboy » Fri Apr 28, 2017 5:15 pm

Hey there's just one more thing puzzling me...it has this voltage adjustment screw, but it has no labels...do you just have to sit there with a voltmeter to find out what it's set to while adjusting it?
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Re: How to use switching power supply :-)

Postby jremington » Fri Apr 28, 2017 11:58 pm

0V is the Arduino/servo GND

Check the DC voltage with a multimeter. If it not correct, then yes, you need to turn the adjustment screw until it is.
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Re: How to use switching power supply :-)

Postby rastoboy » Sat Apr 29, 2017 9:56 am

it's making sense--thank you!
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Re: How to use switching power supply :-)

Postby rastoboy » Sun Apr 30, 2017 1:11 pm

By the way, anyone know of a similar kind of power supply that might come with an actual AC plug?

With y'alls help I got this working just fine, and I was delighted to find it completely solved my servo control problems :-) However last night I finished a new 3d printed chassis for my project and wanted to play with it, but frankly I was terrified to work with this thing while I was drunk. I mean, just no way, even with the contacts covered thoroughly. It'd be nice to have one without exposed inputs, but my searching has not revealed anything like that out there.
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