DMX Address

I have been using a LOR 240V controller for the last two years. I have it plugged into the dmx output of my pixlite 16. I had to make a crossover cable to overcome the difference in wiring protocol used by the two controllers but it has all worked fine and I've had no issues (touch wood). To date I have run all my sequences from LOR S3 advanced.


I just have the sequencer set up so the lor controller is universe 10 channels 1 to 16 and then I set up the pixlite 16 to sent these to dmx output 1.


From what I have been reading people seem to stress that it is important to set the address (or is it start address) of dmx equipment. I have never done this and I was wondering why I haven't had to. I figure it is either I've been lucky and the lor controller was set up with the right address when I got it, or more likely that I am working with a E1.31 network and the pixlite 16 does all the work and converts and sends the data in the right format.


Do you only have to worry about dmx addresses when you are using a dmx controller.


The reason why I'm trying to get a handle on this is I am thinking of getting dmx flood lights. I think I can daisy chain these off the dmx ouput in my pixlite 16. Do I just set it up so the first 3 channels go to the first flood and the next 3 to the subsequent flood, etc or do I have to do something about setting the DMX addresses.


Thanks.

You do need to ensure that the DMX start address is correct. Otherwise your LOR controller's 16 channels may not be 1 to 16.

The method of setting the DMX start address on LOR controllers varies a little by model I believe.

As far as I recall it's the ((unit number - 1) * 16) + 1 but there is a chart somewhere that shows the unit number vs DMX start address.

Thanks David. I just did a google search and it appears when you give each lor controller a unit number it sets the dmx start address. So unit no 1 - start address 1, unit 2 - start address 17 (your formula is right). As I only have one controller it must have been set to unit 1 or I set it to that back at the start (can't remember which). So I was either lucky or I had forgotten what I once knew.


So if my understanding is correct, DMX can only be sent in one universe size lots (so it doesn't use universe numbers), each item has a start address and this address represents the channel number (ie 1 to 512) that it starts taking data from. I guess that each item then just accepts as many channels as it requires from the start address (ie 16 in the case of my lor controller).

Correct. Plain DMX knows nothing about universes, just channels.

So, just thinking out loud here. I can get the dmx start address set when I purchase equipment and/or I can buy a device that sets the address (talking other dmx gear now not lor). If I don't have the device to set the address do I have to have the items joined in sequential order. Eg. Can I have a flood with start address 108 before another dmx item with a start address of 36 in the daisy chain. I'm assuming this is possible otherwise there would be no need for a start address.

Ask the seller to set the DMX flood start addresses for you. They can be difficult to change.

You are correct that it doesn't matter what order they're connected in. Every DMX device sees the same universe of data; the start address is just so it knows which part of that data to respond to. You can even have multiple DMX devices with the same start address doing the same thing.

BundyRoy said:

So, just thinking out loud here. I can get the dmx start address set when I purchase equipment and/or I can buy a device that sets the address (talking other dmx gear now not lor). If I don't have the device to set the address do I have to have the items joined in sequential order. Eg. Can I have a flood with start address 108 before another dmx item with a start address of 36 in the daisy chain. I'm assuming this is possible otherwise there would be no need for a start address.

Click to expand...

What i13 says is correct. you can put them in any order and have multiple items on the same address.
I have even done that on purpose with spots, so I only needed to program 1 element but had multiple spots in various sections of the yard doing the same thing.
If you had multiple items on the same DMX channel, but wanted to control them separately and did not have a programmer, then just run them on a separate universe.

Is most dmx stuff 12V? Is dmx 3 wires, +ve, -ve and data? Can you have items with different voltage in the one daisy chain (obviously the +ve for each item would need to be isolated from the others).

Thanks.

DMX is purely the control method and is not related to the voltage requirements of the equipment.

The + and - are data signals and are usually swing between 0 and 5 Volts relative to the common wire (0V).

BundyRoy said:

Is most dmx stuff 12V? Is dmx 3 wires, +ve, -ve and data? Can you have items with different voltage in the one daisy chain (obviously the +ve for each item would need to be isolated from the others).

Thanks.

Click to expand...

You can run any voltage equipment/lights connected to the DMX chain as the DMX signal is completely separate to the power requirements for any equipment/lighting

Excellent. Thanks again for all the help everyone.

I would buy the programmer.
The only annoying thing is you need to have XLR ends on them, or use an adapter for the three pin waterproof connector, but it is still nice to have these.


Physical order in the chain has no influence on start address.
They all receive the same data.


You need to just set the start addresses properly.


Some floods don't just have RGB. They may have an overall brightness or a strobe channel. Also, they vary a lot. Different batches may have a different RGB order, different channel configuration and I have heard that sometimes floods may not work with a programmer that was from a different batch purchased a long time before.
I have heard people saying that they normally do work across a lot of different floods though.