Multiple ADC100 on USB XP

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Multiple ADC100 on USB XP

Post by Guest » Wed Aug 25, 2004 7:02 pm

I am trying to write a software using more than one ADC100 on the same computer.

One ADC-100 is OK. It uses approx. 50% CPU time. When I start to add more than one it takes almost 100% CPU and the first adapter starts to lose samples.

I am using 1 to 3 ADC100 with the "USB Parallel Port" at a Pentium 4 computer with Winows XP SP1.


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Post by markspencer » Thu Aug 26, 2004 8:33 am


I am sorry to hear that you are experiencing this problem. Since you are using three ADC-100's I expect that you are using the adc100_set_unit to switch between the different units. If not then you will beed to incorporate this into your software.

A possible reason that the ADC-100, is dropping readings is that the data storage is done on the PC and not on board the unit. Thus the more units you add to the PC the less time each will have to collect data. The adc100_set_unit above is used to state which unit is to be used and have the data taken from it.

You might want to consider alternative units to one that does the sampling onboard such as the ADC-212/3.

Best regards,

Mark Spencer


Post by Guest » Thu Aug 26, 2004 9:11 am


The 100% usage of the CPU is starting to happen already during open of the second unit. I am not even near to start reading data.

Yes, I switch units with the adc100_set_unit. I am not surprised it loses data when I am forcing it to run with three units and 100% CPU usage.

How does the driver judge the computer speed? My computer is using hyper-threading, does it fool the driver?

Strangely I had a period of a 36 hours when it worked nice during last weekend. During that period a got all readings correctly and the CPU usage was 50%, running all three units.

Best Regards

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