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error 200077 with digital write, read and internal clock

hi guys,

 

Im trying to follow the example VIs in the help finder. The vi is Write Dig Chan-Int Clk-Dig Start.vi.

This will do exactly what I want in real world where I want to clock in some data and also check for the press of a switch by reading a switch chain.

 

I want to do a Follow the LED test on a board. (This is where a LED is lit up and the user is asked to press the button with the LEd lit up.)

 

I want to use the internal clock for the system for clocking the data into the shift registers.

 

In addition to that the circuit also has a LOAD enable line that is shared by both the LEd chain and the Switch chain. For the LED chain, it is Active high for the Switch chain, it is ACTIVE LOW.

 

FYI, there are 255 LEDs in the chain and 208 switches in the chain.

Here is what I would like to do:

 

1. Using internal clock, clock in the LED data to turn ON a LED

2. Using the same clock, clock the data out of the Switch shift register and then check for a logic 0.

 

I tried using the above mentioned Vi without connecting the board but just having the MYDAQ connected. and when I try to run, I get this error 200077.

Can you guys please help me out here as I am so close to a solution but still its out of reach.

 

thanks,

Kind rEgards,

Labmat.

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labmat,

 

The reason you are getting that error is because the myDAQ doesn't have an internal clock for the DIO lines. myDAQ is limited to software-timed DIO, meaning you have to write a new digital value to the lines in that task everytime you want to update the digital lines.

 

You should look at the example for Digital - SW - Timed Output.VI. This will work with the myDAQ.

 

It's also important to know that there is a forum for academic hardware users, like yourself with the myDAQ.

Aaron W.
National Instruments
CLA, CTA and CPI
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Hi Aaron,

 

thanks for getting back to me. Im only using the MYDAQ for prototyping purposes. in the final system Ill be using a PCI 6536 as the DAQ card for digital IO and USB6008 DAQ for analog.

 

Would this work with the 6536 DAQ?

 

thanks,

Kind Regards,

Labmat

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Yes, the 6536 has an internal clock, so you can do Hardware timed DIO with it. If you need to build software before you have the 6536 then I would use a Simulated Device to allow you to validate your program will work with the hardware.

Aaron W.
National Instruments
CLA, CTA and CPI
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