Electronics > Projects, Designs, and Technical Stuff

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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