Uncalled Digital Channel Turning On

[Matt @ E&M]

I am fairly new to LabView so I have a simple led circuit running on channels 1-5 on my SCB-68 module to turn each led on and off sequencially for a given time. I also put an led on channel 0 and for some reason it is turning on momentarily for a couple ms between each led turning on/off. Channel 0 is not called in my program. This problem is also occuring with other programs that I have been testing.

[AnalogKid2DigitalMan]

Could it be a glitch from port initialization?

[Tom_W_[DE]]

Hi Matt-

AnalogKid is right- it sounds like your ports are just initializing before each operation. This is likely to happen if you are operating on an entire port instead of just individual lines.

Can you let us know a bit more about your hardware setup? The SCB-68 is just a breakout box. Which actual DAQ card are you using?

I have attached a DAQmx VI that writes to the first four lines of port 0 of a device in succession as numeric values. You can also write to individual lines using booleans or arrays of booleans.

An example of how to accomplish this in DAQmx can be found in the NI Example Finder in LabVIEW at Help>Find Examples and then Hardware Input and Output>DAQmx>Digital Generation>Write Dig Chan. For a Traditional DAQ example you can check Hardware Input and Output>Traditional DAQ>Digital Input and Output>[the appropriate card type]>Write to 1 Dig Line.

Please let us know if you have any additional questions.

Thanks and have a great day.

BTW, nice choice on the signature AnalogKid- I'm a huge fan.

Message Edited by Tom W. on 06-07-2005 08:47 AM

[AnalogKid2DigitalMan]

Yes, I think I recall seeing a brief glitch on a PCI-6025 during port init a couple years ago. Did not cause me any issues. Let us know how it works out.

Tom- I am another big fan, as you may have guessed, my handle describes by areas of interest while growing up.