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| Still stumped by USB link |
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| IconicPCB:
Looking into USB2.0 standard the actual USB cable is specified as one twisted pair @Zo= 90 ohms plus two additional non twisted conductors for power. USB2.0 further specifies the delay ( is it group delay inequality ?) and the maximum cable length of 5 meter. I need to repair machine vision based on a USB camera with an overall cable length of close to the limiting value. The cable needs to be ultra flexible as it lives inside a drag chain. Finding such a cable has proven to be difficult. I can get ( out of Sydney ) two pair cat5 ethernet cable which would survive millions of flexures inherent in the application however the characteristic impedance is 100 ohms =/-15%. How critical is the deviation in Z0 form the spec? What problems might be experienced? Is it possible to measure/ evaluate cab;e performance using the USB ports on a PC? But more to the point other than Sydney based LAPP cable is there anyone else who might be able to supply USB cable or similar data cable? |
| SeanB:
How about some USB extenders to use that CAT5 cables in the loom, solving your problem? Try this one for example, https://www.amazon.com/AV-Access-Extender-Operating-Synchronously/dp/B01EV33R8S/ref=sr_1_7?keywords=usb+extender Or this. https://www.ebay.com/itm/USB-Over-Ethernet-Extension-RJ45-Cat5e-Cable-LAN-Adapter-Extender-4-Port-HUB-/391745074308 Just the first sort of sane results from searching and looking at images. |
| ConKbot:
If the cable is shielded pairs, id definitely try it, with something to act as a repeater on either end (active cable, or hubs, etc) so performance won't vary with different hosts plugged in. If it's not shielded pairs, find a cable with shielded pairs, as USB2 has more than a little common mode content, so it will be emitting a lot, and be more susceptible to inference. Especially in an area with motors and motor drives going. |
| SiliconWizard:
Beyond the data, you'll have definite problems with VUSB with cables this long, so you'd need to provide the power supply locally (close to the camera) IMO. |
| fcb:
https://www.newnex.com/usb-3-high-flex-cables.php |
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