How to connect +5V external power supply to USB 6210 to increase current on digital out pins

[scubadood8]

Hi all, I am currently working on a project that requires me to power a linear actuator using a relay (HN22005). I currently have the NI USB 6210. My idea was that i was going to use a digital output to power the relay. After some research i found that the current is limited on the digital outputs to a maximum of 50 mA for all 4 digital terminals. I require a 5V and about 106mA signal to drive the coil in the relay to turn on. I built a pnp transistor circuit to drive the coil and this was successful. However i would like a cleaner solution. After reading through the usb 6210's data sheet i found that i can use an external power supply connected to the +5V terminal in order to increase the maximum current for the digital pins. My confusion is that i do not know how to properly hook up the external power supply in order to increase the maximum current. Is this idea even possible to supply the amount of current i require? and if it is not possible is there another device i can use that will be able to supply the +5V and 106mA i need to turn the relay on? Thanks in advance for any help!

[RyanPoPo]

Hey scubadood,

I think this article may make your question about current output of the 6210 more clear: http://digital.ni.com/public.nsf/allkb/AD24775684BDACA58625766500673D9A?OpenDocument

The 6210 has a self-resetting fuse that caps the total current output using external power at 350 mA. If one pin still cannot supply enough current for you, you can use more pins in parallel to get the maximum 350 mA.

As for hooking up external power, the +5V pin, pin 10 on the 6210, can either be an output or an input. To use it as an input, simply wire your external 5V supply's V+ to this pin and the ground wire to a D GND pin.

Regards,

Ryan

[scubadood8]

Thanks for the response Ryan!

I was able to wire the four digital output pins in parallel to achieve the desired output power. However I do have a concern of damaging the device (NI USB 6210). I have read some articles online that suggest it is possible to damage your device this way. Should i be concerned about damaging my USB 6210 with this settup?

If damage to the device is a concern, would it be better to use a different NI USB device such as the USB 6003 or USB 6009 that will allow at least 150mA output on the +5V terminal ?

Thanks again,

Scubadood

[Dennis_Knutson]

There is no such thing as a 6003. If you mean 6008, then nether it or the 6009 comes close to sourcing that much current. What I've used is uln200x drivers. This topic comes up quite frequently. The thing about the parallel wiring that I don't like is that it reduces the number of separate channels that you can use.

[scubadood8]

Below is the link to the USB 6003 i was refering to. The +5V output terminal is able to supply 150mA.  Do you mean to say that they dont make this product anymore?

http://sine.ni.com/nips/cds/view/p/lang/en/nid/212385

[Dennis_Knutson]

Must be new. I never saw that before.

[Geoff1]

Have you thought about using a solid state relay?

[crossrulz]

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@Geoff1 wrote:

Have you thought about using a solid state relay?

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That is what the HN22005 that the OP is using.Nevermind.  I confused this thread with another one that I was following...

[scubadood8]

I had not considered that. I was just working with what parts were at my disposal. however now i am considering trying a different relay that will not require as high of a current. Would the SSR require less current to turn on but still be able to drive a 24V actuator on the output?

Thanks!

[crossrulz]

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@scubadood8 wrote:

I had not considered that. I was just working with what parts were at my disposal. however now i am considering trying a different relay that will not require as high of a current. Would the SSR require less current to turn on but still be able to drive a 24V actuator on the output?

Thanks!

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Just give Digikey a good search and you'll find something.  The control current is definately less than a normal relay.