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Induce IR signal
Kim
Posts: 52
in AMX Hardware
Hello all!
I had such problem. Eight TVs B&O - everyone control on IR with NI4100, but at sending a signal arises induce signal and there is a false operation of other TVs. Someone collided with such? How to solve a problem?
I had such problem. Eight TVs B&O - everyone control on IR with NI4100, but at sending a signal arises induce signal and there is a false operation of other TVs. Someone collided with such? How to solve a problem?
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These are going to seperate TV which means they are even likely to be in the same room so an irradict high output flasher bouncing signals off the walls isn't likely.
I would disconnect all but one flasher from the NI and see what happens when you send a signal on the connected IR port. If it being induced then they all should controlled still. Try various combination of that and see what happens. But first verify you IR mapping and make sure it isn't going to array that somehow triggers all IR port. Disconnect all but one IR flasher again and send to a port that isn't connected and see if the connected device reacts.
All ports are appointed correctly. TVs are in different rooms, length of wires of 30 meters going together. During the moment of transfer one bulb, on the controller lights up only... Operation of other TVs at commands rare.
IF so... disconnect the Beolink and see if the problem continues... More than likely its not actually an AMX issue but a B&O one whereby the IR signal is being passed via Beolink to the other screens....
If so I think that you have been B&O'd... It's a common problem when trying to control B&O with AMX... I just ran into being B&O'd on a yacht project that I did on B&O where the rear panel IR input jack on the BeoVision7 disables the front panel IR receiver which means that you can not use the Beo4 remote & AMX at the same time... ( ended up sticking a bug receiver to the front of the TV...not exactly a nice solution, but it works for now.... )
There are no Beolink we do not use, have just placed IR emitters on forward panels of TVs... We transfer a signal on twisted pair to big enough distance and as it 455Khz it is possible because of it arises induce...
We have found that on occasion, IR emitters flash too brightly and other devices react when they're not supposed to. I'd try an experiment. Try completely blocking out all IR emitters except one and see if you still get the interference.
We've actually had to put peices of cotton or gauze in front of IR emitters to diffuse the light a bit. this seems to happen in cabinets with closed doors.
Hi Kim
The problem you are experincing are most likely due to the induced codes as you are mentioning, the fact is that when you transmit IR pulses to a IR emitter (essentialy a diode) at 5V with no current limiter it creates alot of RF noice "Great transmitter"
(the B&O codes are at 455Khz)
What happens is this induced RF is picked up on all the other wires, and now you have a great transport as the reciving cables are located right by the very sensetive IR reciver
(The B&O reciver is much more sencetive then standard stuff, normaly a great thing)
Temp Solution:
The quick fix is to add a resistor in series with the positive lead on the IR emitter
(That'll work as a current limiter and minimize the RF transmission, resistor value depends on cable length if the value is too high control will not work relailble when the controlled product is in direct sun/bright light start with 1K ohm)
In addition the reciving antenna can be destroyed by grounding the negativ lead on the IR emitter to the B&O system (as close to the Emitter as posible, this is very effective in solving the problem you are experincing)
Real Solution:
Depend on what system you are using you can inject unmodulated pulse extended signals directly into the IR stream on the B&O Product, this works VERY well
If you are in North America contact B&O head quarters they have a small interface box that'll do the job and the system will work fine with the B&O remote controll at the same time
Best regards
Henrik
Who knew!
The reason you very rarely run in to this problem has to do with how sensitive the IR reciver is on the reciving product (and 455Khz, AM comes to mind with the mental picture of a simpl AM reciver consisting of just a Diode and a capasitor)
Not enough power is recived on the wire to light up the IR emitter, but enougth to control the product never the less thru RF
I did some tests some years back and it was very easy to recreate the problem
If the reciving wire was close to the IR reciver the product was controlled (did not have to be the IR emitter as it's not even transmitting any light when this happens)
(keep in mind the build in AGC on the IR reciver, it's less sensetive in a bright room and more sensetive in a Dark room)
Using Shielded wire will not help much, unless you ground the wire to the controlled product, even if you just short out the IR emitter on the reciving end it'll still be controlled
(at least that was my experince)
I'm by no means a EMI/RF specialist, but hopefuly the end result works out solving the problem for you anyway
Best regards
Henrik
Greetings Henrik,
I use BeoVision 7 and BeoVision 4, and 100 % agree with that that you have written, I use FTP 5e cat, grounding on the contrary did induce more strongly... Or completely suppressed a signal, on a miscellaneous...
I have found a way to use different signals by means of an option at Beovision7 two TV in one room "Link", but it does not turn out to cause yet PC in a mode "Link".
At forum Beoworld has found a way to translate beo4 in constant mode Link " CONFIG? " + "2002", whether tomorrow I shall check up will help me to set it mode PC.
Im from Ukraine. And supports B&O at us practically are not present those. You could not tell more in detail about "a small interface box "?
Best regards