NI 9476 - Actuating a relay

[cuaerospace]

Hello:

I would like to use an NI 9476 to actuate 24 V relays. My setup consists of a 24 V power supply feeding into a CB-37F-HVD terminal block (into the Vsup and COM channels - I chose channel 28 for the Vsup and 19 for the COM). I have 3 relay connected to the terminal block and would like to pass control signals to them.

My impression is that the LabVIEW variable DO28 (the Vsup) needs to be always set to TRUE so that a voltage is applied to our circuit, which I can then switch to LOW when I want to actuate a relay. I have tried to create a program both through scan mode and FPGA but I still can't get a control signal through to the relay. I am using a cRIO 9024. 

I am not sure if the wiring I have is wrong or the LabVIEW logic I have proposed is incorrect.

Your assistance is appreciated, thank you.

Jacek

[crossrulz]

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cuaerospace wrote: I chose channel 28 for the Vsup and 19 for the COM). I have 3 relay connected to the terminal block and would like to pass control signals to them.

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No, you should be connected to PIN 28 and 19 for the supply voltage and ground.

So when you set a digital output on (for instance DO28), then that pin will be connected to your Vsup.  In this case, that would be pin 34.

I recommend a good read through the manual (http://www.ni.com/pdf/manuals/373964d.pdf).  Pages 7 and 8 describe how the device works.

[cuaerospace]

Hi:

I am connected to pins 28 and 19 as you said, for the supply voltage and ground. I then have the relays connected to pins 16, 17 and 18. Their ground connection is ALSO connected to the supply voltage ground in pin 19. Should I be using a separate COM pin for the relays. 

Thanks again.

[crossrulz]

Nope.  Grounds should be all the same.

[cuaerospace]

Ok then perhaps it is the logic that I am trying to implement in LabVIEW. 

What do you recommend as a simple program to, say, turn on and off channel 16? I want to note when I load in my chassis into the project window, slot 5 where the 9476 is placed in, does not register and I cannot discover it as a c series module. May this be a hardware issue?

 Thanks, I appreciate your quick replies. These forums never let me down.

[crossrulz]

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cuaerospace wrote: I want to note when I load in my chassis into the project window, slot 5 where the 9476 is placed in, does not register and I cannot discover it as a c series module. May this be a hardware issue?

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That sounds like a hardware issue.  Does it work in MAX?

[cuaerospace]

I apologize but I do not know how to configure/test a card in MAX. I just fudged around with it and can't seem to test it (if that's what you're alluding to). Do you mean distributed system manager? 

Thanks.

[cuaerospace]

It was a faulty card. We tried another one and it works just fine. thanks.