COM speed - going beyond 250K ? June 28, 2013 05:43PM |
Registered: 10 years ago Posts: 41 |
Anonymous User
Re: COM speed - going beyond 250K ? July 05, 2013 02:51PM |
Re: COM speed - going beyond 250K ? July 06, 2013 07:04AM |
Registered: 13 years ago Posts: 7,616 |
Quote
What is the highest speed that would still work
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Re: COM speed - going beyond 250K ? July 06, 2013 08:46AM |
Registered: 10 years ago Posts: 41 |
Re: COM speed - going beyond 250K ? July 06, 2013 02:35PM |
Admin Registered: 17 years ago Posts: 7,879 |
Re: COM speed - going beyond 250K ? July 07, 2013 07:24AM |
Registered: 13 years ago Posts: 7,616 |
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Printing via USB usually works, but will occasionally have errors due to the PC not responding in real time, or it might disconnect if the ground loop picks up RFI.
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Re: COM speed - going beyond 250K ? July 07, 2013 08:41AM |
Admin Registered: 17 years ago Posts: 7,879 |
Re: COM speed - going beyond 250K ? July 08, 2013 04:40AM |
Registered: 13 years ago Posts: 7,616 |
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I can't think of any professional devices that use USB and are grounded.
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Re: COM speed - going beyond 250K ? July 08, 2013 05:17AM |
Admin Registered: 17 years ago Posts: 7,879 |
Re: COM speed - going beyond 250K ? July 08, 2013 09:29AM |
Registered: 13 years ago Posts: 7,616 |
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I find if I plug machine and PC in the same wall socket or extension I don't get any disconnects but if I plug them in to sockets far apart I will get a disconnect every time I switch the fluorescent light in the same room.
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Re: COM speed - going beyond 250K ? July 08, 2013 09:31AM |
Registered: 11 years ago Posts: 77 |
Re: COM speed - going beyond 250K ? July 08, 2013 09:34AM |
Admin Registered: 17 years ago Posts: 7,879 |
Re: COM speed - going beyond 250K ? July 08, 2013 09:38AM |
Admin Registered: 17 years ago Posts: 7,879 |
Re: COM speed - going beyond 250K ? July 08, 2013 10:16AM |
Registered: 11 years ago Posts: 77 |
Re: COM speed - going beyond 250K ? July 09, 2013 07:41AM |
Registered: 13 years ago Posts: 7,616 |
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Re: COM speed - going beyond 250K ? July 09, 2013 08:16AM |
Admin Registered: 17 years ago Posts: 7,879 |
Anonymous User
Re: COM speed - going beyond 250K ? July 09, 2013 02:59PM |
Re: COM speed - going beyond 250K ? July 09, 2013 03:03PM |
Admin Registered: 17 years ago Posts: 7,879 |
Re: COM speed - going beyond 250K ? July 12, 2013 05:08AM |
Registered: 13 years ago Posts: 39 |
Re: COM speed - going beyond 250K ? July 13, 2013 07:04AM |
Registered: 13 years ago Posts: 7,616 |
Quote
I can change Melzi to include optional optocouplers (with solder jumpers as alternative).
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Re: COM speed - going beyond 250K ? July 13, 2013 10:17AM |
Admin Registered: 17 years ago Posts: 7,879 |
Quote
But, even with differential data, there are times when single-ended signalling is used in the USB: The end-of-packet is signalled with a single-ended-zero (SE0), namely, both D+ and D- in low state. This state last the time of 2 bits. if SE0 last for more than 10ms it means a bus reset.
This single-ended signalling makes the USB quite sensitive to electromagnetic interference, like those I found recently when a hair dryer motor was causing a lot of disconnects in a nearby USB peripheral. And no common-mode filters can be effectively used because these can degrade the SE0 signal...
Re: COM speed - going beyond 250K ? July 30, 2013 05:48PM |
Registered: 10 years ago Posts: 41 |
Re: COM speed - going beyond 250K ? July 30, 2013 08:15PM |
Admin Registered: 17 years ago Posts: 7,879 |