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Ruggedize USB connections for tough environments

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I_B_GREEN
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re: Ruggedize USB connections for tough environments
I_B_GREEN   6/18/2012 6:27:39 PM
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USB isolator dongle?

t.alex
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re: Ruggedize USB connections for tough environments
t.alex   3/4/2012 1:13:23 AM
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I see, but i guess this speed is sufficient for mot applications.

bwf
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re: Ruggedize USB connections for tough environments
bwf   3/2/2012 5:05:10 PM
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Thanks for the great info! Brian Foster

bwf
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re: Ruggedize USB connections for tough environments
bwf   3/2/2012 5:02:54 PM
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Funny you should ask about the host card. I have this on my radar - the project is in the preliminary design phase now. Conec makes a good line of USB cables - you should check them out. Brian Foster

Haldor
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re: Ruggedize USB connections for tough environments
Haldor   3/2/2012 1:43:42 PM
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Does anyone make an industrialized USB expansion card for a PC? Ideally this card would provide galvanic isolation for power,ground and data from the PC. Also does anyone make a bulkhead mount USB connector that properly connects the cable shield to the enclosure of the device. Connecting the shield to chassis ground through the PCB inside a device is problematical from an EMI standpoint. Google "Pin 1 Problem" for an explaination of why this is so if you don't already know about it.

docdivakar
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re: Ruggedize USB connections for tough environments
docdivakar   3/2/2012 7:53:25 AM
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In shielded USB cables, 65% braid seems to be optimal to prevent stray inductances & capacitances from coupling into the cable (it is only low speed cables that are not required to have shielding). I do agree ruggedizing is necessary for industrial applications whereas shielded cables with proper terminations should be sufficient for ground loop avoidance. Here is a link to a whitepaper on EMI testing of USB: http://www.ti.com/sc/docs/apps/msp/intrface/usb/emitest.pdf MP Divakar

bwf
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re: Ruggedize USB connections for tough environments
bwf   2/29/2012 7:12:32 PM
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oops... got my data rates mixed up... Low Speed = 1.5 Mbps Full Speed = 12 Mbps High Speed = 480 Mbps But you get the point... the isolation chips don't support 480 Mbps.

bwf
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re: Ruggedize USB connections for tough environments
bwf   2/29/2012 7:08:06 PM
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Hi - unfortunately, there is a tradeoff when it comes to speed. The isolation chips on the market today will not support USB 2.0 Full Speed (480 Mbps). Therefore your 2.0 compliant device will revert to High Speed (12 Mbps). Thanks for reading the article... Brian

t.alex
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re: Ruggedize USB connections for tough environments
t.alex   2/29/2012 2:47:10 PM
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With isolation, maintaining the original speed is equally important. Is there any tradeoff in speed in this case?

Nazia Gadhia
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re: Ruggedize USB connections for tough environments
Nazia Gadhia   2/29/2012 11:48:03 AM
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I agree with the requirement of ruggedizing the USB connections. The software application, otherwise, has to take care of the error at the protocol level and this would affect the hardware design resource usage as well as the final throughput

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