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USB-RS485 Isolated Adaptor


keith

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No, sorry.  The ISO adapter only runs at a max of 115.

 

Are you running in a commercial environment, or are you just looking for the extra protection an ISO adapter can give?  If you are running in a residential environment, there is no requirement that your low voltage signalling lines be isolated.

 

Isolation is a good idea, but you may not need it - unless it is something you want.

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Yes, it is a commercial application with 4 networks.  They are all running at their maximum capacity.  Without isolators, the commands interfere with those on other networks causing a mess with the programming.  

 

It is a shame that an isolator has to be the bottle neck that cuts my speed by 400%.  Otherwise, I could be much more flexible with networks.  

 

Is there a plan to develop a high-speed isolator?

 

Thanks!

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Yes, it is a commercial application with 4 networks.  They are all running at their maximum capacity.  Without isolators, the commands interfere with those on other networks causing a mess with the programming.  

 

It is a shame that an isolator has to be the bottle neck that cuts my speed by 400%.  Otherwise, I could be much more flexible with networks.  

 

Is there a plan to develop a high-speed isolator?

 

Thanks!

I don't understand.  The only thing the ISO adapter does is add an 'Air Gap' between the Computer and the Controllers.  It has nothing to do with reducing interference.   

 

The Isolated adapter is for electrical reasons, not signalling reasons.  The idea is that the isolated adapter will prevent any high voltage from getting back to the computer should one of the data lines have line voltage get on them somehow.  

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My first show used 4 networks.  LOR had not developed isolators at that time.  Each network worked perfectly by itself, but when any other network was added, the programming signals interfered with each other and the show lost all recognition of its programming.  It was a random mess.  

 

Dan and/or John fabricated isolators from available parts and sent them to me and the problem was cured.  Shortly after that the isolators became available in a commercial form and they accomplished the same thing.

 

Unless something has changed over the years since then, no two large networks will work together without them.  I have never tried to operate a show since then without using isolators because of the personal experience from that first year.

 

I just assumed that the term isolator was adopted because each network's data was blocked from the other networks as was the case for me.

 

So, if that issue has not been addressed in some other form, isolators are mandatory on each of my networks, and 500K speeds can't be utilized.

 

Hence, the need for faster isolators.

 

If this interference issue has otherwise been addressed, please pass that info on to me.  I would like to know how they did it, and would really like to take advantage of the new technology.  It is there for the USB adaptors and the repeaters already, but is of no value to me if I have to use isolators.

 

Thanks!

 

 

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I have asked Dan and John for clarification and if they remember what was going on back then.  This would be the first time I have ever heard of needing an isolated adapter to fix signalling issues.

 

I do know we had issues with USB that required the use of cables with ferrites.  

 

I also know of many users who run multiple 500K adapters, some 4 or more, who do not have signalling issues.   These users have thousands of channels per network.

 

Hopefully they can shed some light on this.

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Looks like I am wrong not ONCE but TWICE.  I think I'll just call it a day after this.

 

1 - I heard back from John, and you learn something new every day.  Once he explained your situation it makes perfect sense.  You have a large display supplied by multiple transformers all of which could be at different ground potentials.  The Isolated adapters fix that problem by only looking at the RS485 signal relative to the ground of the controllers on that segment and then re-transmits that across the air gap relative to ground of the computer.  Otherwise you would be trying to compare the ground reference of the computer to the ground reference of a controllers/networks that could be at a vastly different potentials.  

 

Up to this point all of my experience has been on single supplies with a single reference ground voltage.

 

2 - Then I heard back from Dan.  I was wrong:  According to him, he has successfully tested ISO adapters at 500K.  However, 500K has only been available for a short time so he would have done his testing on newer adapters.  Please test yours and see if they will work at 500K or not.  They should work as there has not been a redesign on those boards, but the components used on earlier versions may simply not be able to run at 500.  The only way to tell is to test.

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