error 200248 - using DAQ USB 6008

[VeeJay]

Hi there,

I keep getting this error 200248 when I am testing the digital output of a DAQ card. I have written a simple program that creates a channel, starts a task and writing a boolean value onto the channel and I am reading the output at the screw terminal using a voltmeter. (Not using DAQ assistant because that works fine, but replacing the DAQ assistant with individual components causes problems)

Here is what happens. DAQ connected to USB -> all DIOs read 5V on voltmeter.

                                  Program started -> All channels read 0V (unless inverted)

                                  Boolean control Pressed -> All channels read 5V (0V when inverted)

 The above happens using DAQ assistant

But, when I use the train of components to start a task->Digital bool sample1 -> , I get 5V ALL the time. Even when I click the Boolean states from on to off. Why does this happen?

Please help me out here.

For the record, The initial pull up states of the DAQ to 5V is really not helping me.

Thanks!

VeeJay

[VeeJay]

The error is 200428

[Ali M]

Hello Vijay, A good way to start troubleshooting your issue is to verify that you are setting up the DAQmx VI’s correctly. The following example which can be found in your LabVIEW shipping examples folder, demonstrates how to properly write values to a digital output channel i.e. Navigate to Help>Find Examples>Hardware Input and Output>DAQmx>Digital Generation>Write Dig Chan.viAdditionally, certain USB devices e.g. the USB-6008/6009/6501 have an internal 4.7 kΩ pull-up resistor, which sets the digital outputs on the device to a logic high start-up state. To obtain a low power-up state on your digital output lines: (a) Put an inverter on each line that needs to be set to logic low at power-up (b) Look into other NI devices that support programmable power-up states. USB M Series devices such as the USB-625x support programmable power up states.Information on DIO devices/power up states can be found at: 1.    http://digital.ni.com/public.nsf/allkb/B4FED0C879BD155F862569ED00142DC7?OpenDocument2.    http://zone.ni.com/devzone/cda/tut/p/id/5034

Regards,

Ali A MohamedApplications EngineerNational Instruments