why is there an error when i try to connect a control in the DO lines to NI Elvis writer under case structure?

[txrxmo]

And if i do this, i do not need a case structure then?

[RavensFan]

I doubt you'd need a case structure.  Your attached VI had another boolean, but it wasn't clear what the purpose of that was.  So you might need a case structure for that one.

Of course it can be connected to the Elvis Writer.  But your VI showed an array going to the Elvis stuff, but your description was only talking about 1 LED.  What are the other lines for?

[txrxmo]

the extra boolean control connected to the LED is something extra as the led im trying to control is just one which is a physical LED. And the other lines are just to meet the case structure's requirements to run the program. Btw, i've replace the result with the Elvis writer but it still says it:

These cannot be wired together because their data types (numeric, string, array, cluster, etc.) do not match. Show the Context Help window to see what data type is required.
The type of the source is boolean (TRUE or FALSE).
The type of the sink is 1-D array of
boolean (TRUE or FALSE).

this is the error

[txrxmo]

I runned the programmed and used a Build Boolean in between of the result and Elivis writer but this error occured;

Specified read or write operation failed, because the number of lines in the data for a channel does not match the number of lines in the channel.

If you are using the Digital Waveform datatype, make sure the number of lines in the digital waveform matches the number of lines in the channel. If you are using boolean data, make sure the array dimension for lines in the data matches the number of lines in the channel.

Number of Lines in Channel: 8
Number of Lines in Data: 1

Task Name: _unnamedTask<4>

what does this mean??

[Dennis_Knutson]

The explanation is quite clear. You have evidently defined the task with 8 channels but the data you are passing only has a single element. So, either your task is incorrect or the data is.

[GregFreeman]

Here, this link will solve all your problems.

[txrxmo]

I still cannot solve the problem. With the circuit of multiple AND and the 2 index array, i am still having the error! 

[Dennis_Knutson]

What did you change? Did you alter the number of channels in the digital task? If so, to what?

[txrxmo]

I changed it to different IO ports. But still cant. Actually i am still very confused with  the number of channels in the digital task...><

[Dennis_Knutson]

It should be simple. Each line is a channel. If you want a single line to match your code, you would just specify digital output 0 for example. Don't select a port since that is multiple lines.