Forum: RDM Timing Discussion
May 26th, 2015
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Replies: 10
Views: 22,065
Looks like a very good reason not to use a...
Looks like a very good reason not to use a timeout to detect end of packet! However if this is unavoidable then the specification can still be met:
Set the timeout to 1.05mS
When a timout is...
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Forum: RDM General Implementation Discussion
January 15th, 2015
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Replies: 1
Views: 9,339
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Forum: RDM General Implementation Discussion
March 3rd, 2012
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Replies: 6
Views: 14,598
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Forum: RDM Physical Layer/Hardware Discussion
June 12th, 2009
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Replies: 24
Views: 37,463
I stand ( well, sit actually... ) corrected!
...
I stand ( well, sit actually... ) corrected!
I don't have a copy of the RDM spec to hand, I was intending to check that figure this evening. This means that the UART will need to be run at 50kbps...
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Forum: RDM Physical Layer/Hardware Discussion
June 12th, 2009
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Replies: 24
Views: 37,463
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Forum: RDM Physical Layer/Hardware Discussion
June 12th, 2009
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Replies: 24
Views: 37,463
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Forum: RDM Timing Discussion
May 23rd, 2009
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Replies: 6
Views: 23,703
Having used several different manufacturer's...
Having used several different manufacturer's offerings ( but not for DMX ), I am pretty sure that you are still correct. These all needed custom drivers, which caused no end of problems, so I now use...
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Forum: RDM Physical Layer/Hardware Discussion
August 5th, 2008
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Replies: 7
Views: 17,061
A capacitor after the diode will sort out the...
A capacitor after the diode will sort out the impedance issue, it doesn't need to be particularly large as the impedance is only relevant for higher frequencies - 100nF would probably be enough. Add...
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Forum: RDM Physical Layer/Hardware Discussion
December 5th, 2006
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Replies: 3
Views: 15,110
Th equations are:
Vbias = Vcc * 1 / ( 1 /...
Th equations are:
Vbias = Vcc * 1 / ( 1 / Rt1 + 1 / Rt2 ) / ( 1 / ( 1 / Rt1 + 1 / Rt2 ) + R1 + R2 )
Rterm = 1 / ( 1 / Rt1 + 1 / ( R1 + R2 ) )
The specification requires Vbias to be...
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Forum: RDM Physical Layer/Hardware Discussion
November 30th, 2006
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Replies: 3
Views: 15,110
Change Rt1 to 150R and R1, R2 to 390R.
This...
Change Rt1 to 150R and R1, R2 to 390R.
This gives almost exactly the same bias voltage, and is reasonably close to the 120R impedance requirement ( 126R ). Using difficult to obtain ( in small...
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Forum: RDM Interpretation Questions
October 17th, 2006
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Replies: 4
Views: 13,679
As Scott has already mentioned in a separate...
As Scott has already mentioned in a separate thread, sub-devices where intended for dimmers, where each sub-device is identical ( or at least very similar, eg. non-dim or 2.5K/5K channels ). Where...
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Forum: RDM General Implementation Discussion
September 24th, 2006
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Replies: 3
Views: 13,110
You are forgetting two things:
The SN75176...
You are forgetting two things:
The SN75176 is a very old device, and more modern transceivers usually guarantee that a 0V input will give a high output. The MAX485 datasheet says: "The receiver...
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Forum: RDM Interpretation Questions
July 3rd, 2006
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Replies: 1
Views: 10,494
Error counters
10.2.1 says 'Short Message - The message ended before the Message Length field was received', and the other two error counters only count messages with a matching UID. What should happen if a message...
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