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How can we discover the DALI devices in a DALI bus? What is the command? What is the reply from devices for the command? If possible can you provide me a suitable resource where I can research more on this?

Null
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sharath
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    Basically you are asking how to use electronic products, and the info would be in product manuals or DALI specification which is not freely available. – Justme Nov 25 '21 at 10:27
  • Disagree with the votes to close because the question is at the command level so is about the protocol. It’s not about a product through it’s user interface. – Martin Nov 27 '21 at 15:14

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To discover if there are any DALI gear on the bus, you could use command 145 QUERY CONTROL GEAR PRESENT, opcode byte 0x91 with the broadcast address.

  • If you get no response, no control gear are present: connected & powered on.
  • If you get any response (a valid Manchester decoded byte) or any edges during the response time window (collisions) then there is at least one control gear present: connected and powered on. Unfortunately you cannot be sure that even a response which appears to not have collisions (all the bits meet their timing specifications and it decodes successfully) means that there is exactly one gear present - it is possible for multiple gear to coincide their response timing.

You can use the same command but sent with Short Addressing to scan through all 64 short addresses to see if there is a gear with that short address on the bus. These messages can be sent out quickly in a few seconds. But there can be unaddressed gear on the bus (ones which do not yet have a short address).

Command 150 QUERY MISSING SHORT ADDRESS, opcode 0x96, sent broadcast will tell if you if there are any such unaddressed gear. If so, you would have to go through the random addressing procedure to discover them using their random addresses and program short addresses into them.

The same idea can be used for discovering control devices which use a different message format than the gear.

The standard you should buy to understand this is IEC62386-102, however you can find DALI guides around the internet which have most of the information you'd need but it might be slightly outdated.

Martin
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  • once the broadcast message is sent, how do we know that which gear is sending the response. As I read in the manual gear response would be 8 bits right? there is no mention of address as it is there in the request format. I looked on many resource I didn't find the exact command format of the responses – sharath Nov 30 '21 at 04:49
  • The response doesn't contain the address so you don't know. That must be the case for what I said about the possibility of multiple gears sending exactly coincident timing, it must be the same message for all the edges to be coincident (within a few microseconds). – Martin Dec 01 '21 at 09:17
  • The format of the response is in the standards - value in part 102, timing in part 101. – Martin Dec 01 '21 at 09:25