Triggering multiple digital outputs with myDAQ

[kasic]

Hey everyone,

I'm new to NI and I am having some trouble debugging my project.  I am making a battery backup system which would kick in to run a fan once the DC power supply drops below a certain limit.  I have attached my VI for reference.  The Front Panel seems to work fine.  However when I connect the hardware and have an LED connected to Line 6 (DC Power Supply Indicator) and an LED connected to Line 7 (Battery Backup Indicator) the light for DC power will constantly stay on when in Battery mode.  The LED for the Battery Backup will function as expected... ON when in Battery Backup Mode and OFF when in DC Power Mode.

I hope someone can help me out.  Thanks,

Pete

[dbell0971]

Hi kasic,

Can you post screenshots of your front panel when it is in Battery mode?

Thanks,

David B

National Instruments

Applications Engineer

[kasic]

Hi David,

I appreciate your interest.  Please find a screen shot of my front panel and my schematic (probed on the digital output data input wires) attached.

Also a note: When I probe the data input into the DAQ Assistant for both the Battery and DC Supply a Boolean response is the output.  The Battery Boolean will flip from TRUE to FALSE (and vice versa) as it should when in battery mode but the DC Boolean stays TRUE regardless.  This is weired especially that the LEDs on the front panel operate as they should.  I'm really stumped.

Thanks,

Pete

[dbell0971]

Hi kasic,

I could be very confused, but it looks like the DC Power LED is false in the screenshot that you posted.  It looks like the DC Voltage is at 3.9, the battery set point is at 4.31, and that the DC Power LED is off.  Is this what you were expecting to see?

Also, it looks like you are using the "Run Continuously" button at the top of the screen.  Because you have everything inside of a while loop, you only need to hit the "run" button instead.

Best regards,

David B

National Instruments

Applications Engineer

[kasic]

Hi David,

Thanks for the reply.

True.. the front panel does operate as required.  However the output to my protoboard from the myDAQ does not.  As you can see in the attachment in the Probe Window watch... both outputs to the myDAQ Assistant (Digital Outputs) is producing a TRUE result.  But we can see that this is not correct based on the Front Panel LEDs and the Boolean Indicators under the Graphs.

I have physical LEDs attached to Digital Output 6 and 7 on the myDAQ.  The DC Power Supply LED does not turn off when in Battery Mode but the Battery Mode LED does turn off when in DC Power Mode.

I hope I'm not making this any more confusing.

Thanks for the tip on the Run 😉

Pete

[dbell0971]

Hi kasic,

Have you tried directly wiring the dynamic data type into the output DAQ Assistant?  I don't know what type your dynamic data is, but if outputs correctly to the front panel, it may output correctly to the DAQ Assistant.  What kind of data is your dynamic data type?  Is it converted to an array of booleans?

Thanks,

David B

National Instruments

Applications Engineer