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adc100_open_unit and F10 key questions

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adc100_open_unit and F10 key questions

Postby armitstead » Wed Aug 11, 2004 10:38 am

I've written an application in VB6 for the ADC 100, it works well, however
I have a couple of questions re the use of the dll.

1) If I call adc100_open_unit it returns -1 even if the ADC 100 is not
connected to the parallel port. In fact all the calls I use to the dll
return the same value whether the device is connected or not,
except for the data of course (which is zero if not connected).
How do I determine if a successful connection has been made ?

2) In the documentation it explains that a stuck trigger can be released by
pressing the F10 key (for 32 bit Win apps). This does not work and the
PC hangs forever. Why's this ?

I'm using Win XP, IBM A31p laptop and your latest drivers from the web.

Thanks.
armitstead
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Postby Sarah » Wed Aug 11, 2004 11:25 am

Hi Armitstead

Thank you for your post.

In answer to your questions:

1) You are seeing the results you are seeing because it is not possible to tell if the ADC-100 is present or not. The same is true in Picoscope - the software has to assume that the unit is present. So unfortunately you will not be able to determine if a connection has been made.

2) The reason the triggering seems to "stick" is that it is waiting for a trigger event and is devoting all of the processing time to waiting for this event. Unfortunately the F10 function does not work with the ADC-100 unit. Instead to stop the trigger you need to click on "Stop" and whilst it is appears that it is not working, if you then cause the trigger to occur, it will trigger and then stop immediately after. The other option is to use a slower timebase and use auto-triggering which will prevent the "sticking" effect that you are experiencing.

Hope this helps

Best Regards
Sarah
 

Postby armitstead » Wed Aug 11, 2004 12:21 pm

Thanks for the quick reply Sarah,
I tried setting a slow sample rate using adc100_set_interval and it makes
no difference, i.e. 5 samples in 5,000,000 uS (1 sample / sec).
When you explain the dll uses the whole of the PC's processing to look
for the trigger, you really mean it, not even ctrl/alt/del works.
It would be a nice addition to a future driver update to include a time out
in waiting for the trigger in the adc100_set_trigger call.
I got round this issue by writing the trigger logic in my app code and
polling the trigger channel using adc100_get_value, the nature of the
application is such that uS accuracy on the trigger timing is not important.
Thanks again.
armitstead
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Joined: Mon Aug 09, 2004 12:22 pm


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