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USB data transfer speed

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USB data transfer speed

Postby SteveW » Mon Oct 13, 2003 3:20 pm

Hi,

I am considering using the ADC-100 together with the PP196 USB adapter and your C drivers to interface to a PC running Windows XP.

I need to continuously sample (stream) 2 channels at 1000Hz each. The signals are bipolar +-1v.

Question 1:
I understand the PP196 has its own hardware timer - how close to 1000Hz will it acheive?

Question 2: Can the PP196 continuously send 2 * 1000Hz sample streams up the USB link?

Question 3: If I was to use a block sampling mode how fast can the PP196 transmit data up the USB link after the data collection block, ie: how long does it take in ms to send 1 sample ?

Thanks for your help.

Steven Watts
SteveW
 

Postby markspencer » Tue Oct 14, 2003 7:54 am

Hi,

The USB to parallel port adaptor can download 1000 Hz in streaming mode continuously.

The unit does not have any memory on board and thus does not collect a block of data and then download it, the only units that do this is the ADC2xx range. Therefore it downloads the readings one at a time again with streaming and buffers it in the driver functions.

We have had some issues brought to our attention recently by other customers using the ADC-100 and USB to parallel port adaptor, which are listed in the Buglist. These are due to be resolved in the coming months, but if you do have any problems with it please bring this to our attention.

Best regards,
Regards,

Mark Spencer
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USB Data transfer speed #2

Postby SteveW » Tue Oct 14, 2003 8:53 am

Hi Mark,

Thankyou for your reply.

Just to clarify - can the USB to parallel port adapter stream 2 channels at 1000Hz continuously or is this 1 channel at 1000Hz continuously?

Are you able to say roughly how long it takes to send 1 sample up the USB link?

Regards

Steven Watts
SteveW
 

Postby markspencer » Wed Oct 15, 2003 7:13 am

Hi,

It is 1000 Hz through the USB by streaming for both channels.

I would not like to make a judgement on transfer rate for one bit through the USB.

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Postby chrisb » Mon Jan 26, 2004 10:25 am

Hi,

We are trying to use the USB adaptor with the ADC-11/12. You say The USB to parallel port adaptor can download 1000 Hz in streaming mode continuously. Does this mean it can send 1000 Samples/second MAXIMUM from the ADC to the PC?

If so - the ADC-11/12 is supposed to sample at 10000 Samples/sec - how is it that all this information can get from the ADC to the PC as it would appear that the USB adaptor is a bottleneck?

Best Regards,

Chris
chrisb
 

Postby markspencer » Tue Jan 27, 2004 8:14 am

Hi,

Thank you for your email.

The number of data readings passed across the parallel port is PC dependent, but most have a 100ksps. Unfortunately, the parallel port cannot stream.

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Mark Spencer
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