[mike sr1]

Hello,
I am looking for a way to isolate the long USB cables at the machine computer to supress electrical spikes, anyone have any input on this?
I was able to get by with this problem as it was only occasional but I added a pendant that has a 10 foot usb cable and it picks up noise that wasnt a problem before.


The HF on the welder is a major problem, but I dont use it when machining, but the compressor and AC start at any time and that is a problem.

There are noise isolators available from about 30 dollars to several hundred or more.

I was wondering if anyone had tried any of these or had experience with them?

Any input appreciated

thanks

[SCzEngrgGroup]

Are you just running a really long cable, or do you have a hub in it? USB was never intended for long distance. Even 10 feet is really pushing things. Adding a hub in the middle will significantly improve reliability. There are also devices out there designed specifically as USB range extenders, that convert the signals to optical, or some different electrical format, then back again at the far end.

Regards,
Ray L.

[mike sr1]

The item mentioned will do that and I may have to resort to that.
In the meantime I wrapped all the loose cabling and packed steel wool around it, that may be enough RF suppression to do it or at least get below the critical point on the noise, time will tell.

I have been a ham for years and I learned long ago that getting rid of RF noise is a real problem, and has diminishing returns at best with the simpler fixes.

I am hoping that someone has tried one of these supressors and what luck they had with it.

thanks

[mactec54]

mike sr1

A USB Cable with Ferrite Chokes on, will most likely solve your problem

[SCzEngrgGroup]

mike sr1

A USB Cable with Ferrite Chokes on, will most likely solve your problem

Having spent far too many years doing EMI/RFI compliance work on a wide range of consumer products, I can tell you that chokes are extremely unlikely to make any difference at all in the reliability of a USB device. The purpose of ferrite chokes is to reduce emissions radiated FROM the cable itself. The frequencies they act on originate within the PC or device itself, not the relatively low frequencies of the USB devices. They do essentially nothing in terms of suppression of noise induced INTO the cable from external EMI/RFI, which is clearly the problem here. Also, chokes operate on VERY high frequencies - typical hundreds of MHz. FAR beyond the operating frequency of USB.

Regards,
Ray L.

[mactec54]

SCzEngrgGroup

I would suggest he tries it, any USB cable that is over 6" should have them, if he wants a good clean signal,any devices that you buy today almost all will come with them on there USB cables

The extender that you suggested would be of no use, you obviously have never used or tried one, for an application like what he needs it for, it would be totally impractical for his use

Also what you just posted is incorrect, the cable will be protected from outside induced EMI/RFI, if his cable is shielded & with the Ferrite chokes, you are misinformed if you think different

[SCzEngrgGroup]

SCzEngrgGroup

I would suggest he tries it, any USB cable that is over 6" should have them, if he wants a good clean signal,any devices that you buy today almost all will come with them on there USB cables

The extender that you suggested would be of no use, you obviously have never used or tried one, for an application like what he needs it for, it would be totally impractical for his use

Also what you just posted is incorrect, the cable will be protected from outside induced EMI/RFI, if his cable is shielded & with the Ferrite chokes, you are misinformed if you think different

Mactec,

How many hours have you spent actually working in an EMI/RFI compliance testing lab MAKING consumer electronic devices pass US and international EMI/RFI compliance certification tests? I did it for MANY years, on MANY products, including computers, music synthesizers, digital still and video cameras, and many other products. So, I KNOW from years of hands-on experience exactly what those ferrites are for, and what they actually do, and don't, do. What is your background and experience in this area that allows you do declare so confidently that I am "misinformed"?

Regards,
Ray L.

[underthetire]

What about using braided shielding around the cable and earth bond it one one end. I've gotten away with that on occasion for low voltage signal cable.

Sent from my G-Tab Quantum using Tapatalk

[mactec54]

What about using braided shielding around the cable and earth bond it one one end. I've gotten away with that on occasion for low voltage signal cable.

That could become an antenna by adding a shield to the outside, with it being such a long cable, as well you can buy the cable that he needs already with a shield & the ferrites in place, cheaper than you could get the braided shield for

[mactec54]

How many hours have you spent actually working in an EMI/RFI compliance testing lab MAKING consumer electronic devices pass US and international EMI/RFI compliance certification tests? I did it for MANY years, on MANY products, including computers, music synthesizers, digital still and video cameras, and many other products. So, I KNOW from years of hands-on experience exactly what those ferrites are for, and what they actually do, and don't, do. What is your background and experience in this area that allows you do declare so confidently that I am "misinformed"?

I don't think for a minute as to what you said is all incorrect

Just the most important part you got wrong, so that makes you misinformed, as to how the shield & ferrites can work together to protect against outside induced EMI/RFI

A small part of my background was Design/Build in Nuclear magnetic resonance (NMR) but I'm not on here to brag about what I have achieved, as some on here do

[tmarks11]

You are both right...

Ray is right: putting chokes on wiring coming out of the machines blocks high frequency noise generated internally by the machine by by oscillators, switching of transistors, etc, which would otherwise become a radiated EM issue, causing said device to fail EMI certification.

Mactec is right: adding chokes on signal wiring (like USB) prevents the signal wire from becoming an antenna to pick up high frequency radiation coming from the machinery that Ray failed to protect properly . Choke provides the impedance to block high frequency signals while passing lower frequency and DC.

Back to the OP: he is having problems when a large induction motor cycles on/off. Think this is an EMI issue, or a brown-out issue?

I don't think a choke would solve this, because we aren't talking about high frequency noise here, where a choke is going to do you the most good. This is looking like a one time pulse, which will probably make it through the choke.

[SCzEngrgGroup]

You are both right...

Ray is right: putting chokes on wiring coming out of the machines blocks high frequency noise generated internally by the machine by by oscillators, switching of transistors, etc, which would otherwise become a radiated EM issue, causing said device to fail EMI certification.

Mactec is right: adding chokes on signal wiring (like USB) prevents the signal wire from becoming an antenna to pick up high frequency radiation coming from the machinery that Ray failed to protect properly . Choke provides the impedance to block high frequency signals while passing lower frequency and DC.

Back to the OP: he is having problems when a large induction motor cycles on/off. Think this is an EMI issue, or a brown-out issue?

I don't think a choke would solve this, because we aren't talking about high frequency noise here, where a choke is going to do you the most good. This is looking like a one time pulse, which will probably make it through the choke.

I agree with almost everything you've said. I even agree the chokes will reduce VERY high frequency noise picked up by the cable from entering the machine and the device, but my point was that's very unlikely to help in the frequency range that is most likely causing the problem here. While USB2.0 is capable of operating at 480Mb/sec, the fact is 99+% of USB devices actually operate at USB 1.0 speed, which is only 12Mb/sec - anything but fast. The USB 1.0 PHY itself will filter out the kind of noise the chokes would affect, and the chokes would make no functional difference in operation of the interface. Noise from a VFD is VERY broad spectrum, and knocking down only the very high frequencies with chokes will be of little or no practical benefit.

Regards,
Ray L.

[mactec54]

tmarks11

I only went off what he Posted (I was able to get by with this problem as it was only occasional but I added a pendant that has a 10 foot usb cable and it picks up noise that wasn't a problem before.)

Just the though of a 10 foot USB Cable, is a problem, so he needs this to be the best it can be, with all the bells & whistles

It to could be a power surge problem as well, but his USB will only be 5V & the computer would shut down if the power surge was to great

To solve the power spike with the AC & compressor you could, add a soft start to each of them, that would solve that problem, plus you will use a lot less power

[tmarks11]

...I added a pendant that has a 10 foot usb cable and it picks up noise that wasnt a problem before....the compressor and AC start at any time and that is a problem

I think we need to drill down a little. What is the symptom that you are trying to get rid of? When the AC or the air compressor starts, what effect do you see on the computer?

[mike sr1]

The problem came about when I added a pendant with a 10 foot cable on it, it could be shortened but then I couldnt move it away from the computer, I am going to try the makeshift shielding to see what happens. The cable is approximately 16 feet long now and thats asking for a problem with USB.
I also have cables with the ferrites on them, that will be next if this doesnt work. It is only an intermittent problem, doesnt seem to happen everytime the compressor or AC cycles.

I was asking mainly about the USB isolaters, that are on ebay etc, they start about 30 dollars or so and go up from there. If someone has tried one, I would like to hear how it worked out for them.

thanks

edit: There doesnt seem to be any shortage of power, no lights dimming etc when this occurs.

[SCzEngrgGroup]

This is the kind of device I would try for that situation:

Icron USB Ranger 2014 2 0 Cat 5 4 Port Range Extender High Speed Extremeusb | eBay

Regards,
Ray L.

[shred]

Chokes might help. They can improve noise-rejection from outside sources on USB. No idea if they will in this case.

My experience is from developing and testing the worlds first "legacy free" PC back in the last century for a major PC company. Early USB controllers would freak out at everything from static to nearby lights and ferrites did help mitigate occurrences of that. Lots of late nights in the development and EMI labs...

[mountaindew]

Chokes might help. They can improve noise-rejection from outside sources on USB. No idea if they will in this case.

My experience is from developing and testing the worlds first "legacy free" PC back in the last century for a major PC company. Early USB controllers would freak out at everything from static to nearby lights and ferrites did help mitigate occurrences of that. Lots of late nights in the development and EMI labs...

I will bite on this!
What is the worlds first legacy free PC?
Please explain more!
md

[zephyr9900]

What is the worlds first legacy free PC?

I'm kinda curious about this too. As of this past weekend I have no more MFM hard drives or ISA expansion cards in the house--but I am holding onto the Mac+...

Randy

[SCzEngrgGroup]

A "legacy-free PC" - Think of some of the super cheap PCs that started coming out about 15 years ago. No expansion slots, no floppy drives, etc. In short, little or no internal hardware expansion capability. Any expansion was through a USB or FireWire port, or something similar. The iMac would be the Apple equivalent.

Regards,
Ray L.