k8055

[the.dwarfer]

That one works but there is a 5 sec pause between pushing the button and the action happening on the card. is there any way to reduce or remove this pause?

[therealkilkenny]

Hi Dwarfer,

Try highlighting the execution and following through what is happening in the program. That way you will learn how it works and be able to debug it.

I wonder if some of the problem is that you are opening two devices with different addresses, but when you make a call to one of the boards (to set the digital outputs for example) you are not specifing which board. I think this is a weakness of the dll.

If you go through Josephs vi you may find a couple of extra non-essential bits of code and also a bug (hint: look at the second sequence structure. It sequences through the panes 0, 1, 2, 3, etc. Check out what it is doing and change it to the correct order )

Something you may want to think about. Only make a call to the board(s) if you need to. If nothing has changed don't call the board. You could use an event structure for this. One of my vi's worked on this.

Phil

[abcbjoseph]

Hi

Do you have any idea how to extend the pulse output to different channels of the same card.ive succeded in getting the first channel working,just was wondering if i could extend it to channel 2,3 of the same card.Can be the same pulse,but diffrent channels at the same time.Dont think it will work if we put a delay now.Any clues?

Regards

Joseph

[therealkilkenny]

Hi Joseph,

Hmmm.... not sure how your going to tackle this one. The problem with these cards is that they are VERY basic and as far as i am aware you can only get out what you put in (i.e. you get a signal out corresponding to the command called in the program). Ideally what you need to do is to tell the card what to do and then set it going (i.e. have on-board memory so that the execution and timing is handled on the card rather than the computer). Alas i don't think you can do this.

My guess is that you need to need to repeatedly write all the values for all channels (or at least the ones you want to use) all the time (i.e. If using first four channels: have a loop out-putting on, off, on, on for channels 0-3 having states on, off, on, on. In the next iteration of your vi write the opposite to all the channels - off, on, off, off. Of course in the dll you write values of 0 and 1 rather than on, off).

Does that help? Btw, what are you using the cards for? Just interested.

Phil

[abcbjoseph]

Hi Phil,

I noe this is goin to be a silly question,but how dose the dll know which is channel 0,1,2 etc.The digitals I understood it as because they were in order,but how dose it actually recognise it.I actually did try to pulse output through channel 0 of two diffrent cards,but that is very slow,because of the problem of calling form a single dll i think,tough it works,it dose not give a pulse at the desired frequency.We are using these cards to generate digital and pulse signals for testing our turnkey systems,during FAT.

Also i didnt quite get the diffrent loop idea just attaching wat ive managed to do till now.

Regards

Joseph

[therealkilkenny]

Hi Joseph,

I'm not sure if i've understood you correctly, but I've attached a vi that turns channels 1,3,5,7 on and 2,4,6,8 off and then reverses it. I hope it works.

A couple of thoughts: Have you read the software manual for the dll that came from velleman - it's useful to understand the right calls to make to the dll. Also, sequence structures are bad news. much better to use a flat sequence structure as i've done in this case. I also want to say that it's not elegant - there are much better ways to do this, but at least it might get you off the ground.

Let me know how you go.

Phil

[abcbjoseph]

Hi Phil,

It dose work fine.I also noticed that if all the channels work together giving pulse outputs,its unable to get a high frequency output,from each channel.So its better to run few channels to get a hig frequency pulse output.We also figured a way to get it onto the PLC.Just for info tatz all.

Cheerz for ta help.Will get back if I am stuck up with sumtin else.

Regards

Joseph

[therealkilkenny]

Hi Joseph,

Thats good. How did you get it onto the PLC? I'd be interested in seeing your code when you've got it all working.

Best regards,

Phil

[Mobins]

Greetings.

Sorry to revive a dead thread, but i am a noob trying to get some simple values from a thermal sensor plugged into a K8055. I am using Labview 8.5 on vista. I have opened you .VI and can make the output LED's come on, but cant figure out how to use the DAQ assistant... is this possible with the student version of labview? Any help would be greatly appreciated

Thanks

[therealkilkenny]

Hi Mobins,

What type of thermal sensor are you trying to read? If it is a thermocouple then you can forget about it. The voltage from a thermocouple is miniscule and needs to be amplified in order to get it to a level where it can be digitised. Think about the measurement you are trying to make - is it voltage, resistance etc.

The K8055 is a very basic board that is not really designed for data acquisition. The DAQ assitant won't work with it because the hardware is incompatible. To use the DAQ assistant you need to be using National Instruments hardware (or compatible hardware from another vendor).

If you want to measure temperature then i suggest that you use some NI hardware or the TC08 from Picotech. A cheaper option is a device from Phidgets, but you will probably have to have some LabVIEW experience to use it. I built my own device for measuring temperature. Maxim IC produce a chip that ampliflys and digitises a thermocouple reading. I then used a bit of kit from DLP Design to comunicate with it over SPI. 

All the best,

Phil