12V DC ,10 amp relay for compactRIO

[freemason]

Hello,

Can any body tell me, if there are any 12VDC, 10-16 amp relay modules available for compactRIO directly form NI or third party.

I want to control the motors that draw upto 10amp 12V DC. i have bunch of DPDT mechanical coil relays but they are bulky and heavy.

solid state relays have a small voltage drop but which is not acceptable in my application.

Please help,

Thanks in advance

[AnalogKid2DigitalMan]

freemason:

Can you clarify is bulky and heavy? I think there are automotive style relays that handle that amp range and are about 1 cubic inch in volume, weight is proabably on the order of an ounce or two. Would that suffice? What are your limitations for coil voltage and coil current?

-AK2DM

[Verne_D]

We've got the NI 9481 and 9485 for the cRIO but they don't approach those current requirements.

[freemason]

Thanks verne,

I came across those already, do you know if any third party modules are avaialbale?

[Verne_D]

I can't find one. Here's the list of modules we've got. Looks like there's a solenoid one that will do 1.4A, but that's not close either. 10A relays are usually pretty big and I don't know if they lend themselves to the c-series carrier form factor. Wish I had more for you!

[AnalogKid2DigitalMan]

One example of numerous sub-cubic inch, 1/4oz 10A relays that are available:

http://www.alliedelec.com/Images/Products/Datasheets/BM/AMERICAN_ZETTLER_INC/686-0272.PDF

-AK2DM

[mikealder]

If you get a 9977 cRIO filler module you have around 13MM between the blank PCB and the top of the case, you should be able to get Omron G6RL SPDT relays to fit as they are only 12,3MM in height then build your own board, use a digital output module in another slot to control the relay drive circuits - Messy but will keep everything in a single "brick" All the other higher current relays I have looked in to simply won't fit the form factor of the cRIO module - Mike

[freemason]

Thank you all,

I will try to use the automotive relays, but still not satisfied.

I was thinking to use a 9477 DO sinking module with 10 channels in parallel to the 10A pump so it will sink 10A current. I can use a PS or a battery to the pump directly.

since it has total 32 channels i can still drive other pumps that are present in the system which consume ~ 2amp each (2 ch in parallel)

Can it work this way??

other thing in mind:  can i use 9474/9475 DO sourcing o/p multiple in parallel to obtain higher current drive to run the small pumps.(2 amp each) 

- need help

Thanks guys

[freemason]

This way i can totally avoid relays?

is this feasible without any damage to the CRIO or chasis?

[K C]

Hi,

Driving a motor directly from a digital output is dangerous I think.

The motor can generate large voltage peaks that can destroy your digital output.

If you place more outputs in parallel, you can sink more current but if one or more outputs are failing the other outputs will have to handle more current and get defective and so on.

In addition, if not all outputs have the same resistance the current will not be the same for all outputs.

If you do not want to use a (normal) relay, you can use a solid-state relay or build an output with a switch MosFET.

Kees