Many USB Devices

[armmic]

Hi

I have a production test system which tests 4 devices simultaneously. The system has an ever increasing number of instruments and peripherals as we perform upgrades and extend the system's capabilities. We are using USB for a lot of devices - Keysight chassis with DMM and scope cards, Raspberry Pi using a USB/UART interface, NFC readers, mouse, keyboard, printer, etc We have 25+ devices plugged in (and need them all!).

We have experienced some issues whereby some peripherals may be 'lost' - mouse, keyboard etc.

I'm looking for advice in terms of how to 'architect' the USB systems - i.e. what hubs are best, do I need multiple controllers, dedicated PCI cards, do's and don'ts...

Thanks

Mike 

[crossrulz]

I generally avoid USB if at all possible. I prefer using Ethernet whenever possible as it just works so much more reliably.

But if you insist on USB, then you want to have some good, externally powered, commercial grade USB hubs. I am personally a fan of StarTech. I am actively using a ST7300USBME (7 ports) on my desk and never had a problem. If you really need a lot of ports, there is a 16-port option: 5G16AINDS-USB-A-HUB. You will need to get a power supply that can handle the current capability you may need. Do not rely on bus power for the hub. The lack of power on the bus is likely why things "turn off" on you.

[armmic]

Thanks for your reply.

I'm stuck with USB for the time being - legacy.

I use StarTech (ST1030USBM) for new requirements - with a dedicated power supply, but haven't gone through the system exchanging older ones out - may be worthwhile. 

I'll look into swapping the rest out.

Any idea if adding a PCI based USB card would be any help?

Thanks again

[crossrulz]

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@armmic wrote:

Any idea if adding a PCI based USB card would be any help?

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I have no experience with using a PCI USB card. My main concern there would be to make sure your computer power supply can handle the current.

[rolfk]

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@armmic wrote:

Any idea if adding a PCI based USB card would be any help?

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Since you are at Startech already, they usually work quite good. However, the instability of USB is not just the hub! Many USB devices are designed as consumer grade goods. If they don't crash within an hour of powering them up they are declared good for sale and handed over to the manufacturing department with the strong intention to never look at the design documentation again under any circumstances.

Firmware bugs happen on any device, but USB devices often use USB for one main reason besides being universal: the low cost! And that translates often throughout the entire design including after design care, and let's not even talk about after sales support.