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Training for DMX?


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Hi there,

 

I was wondering how do I go about getting training for the use of DMX? I have noticed that DMX is starting to become a big thing in theatres and would like some training on the use of DMX but dont know were to start.

 

Any advice please?

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Start with the Wiki here http://www.blue-room.org.uk/wiki/DMX

 

Put simply - each unit will have a DMX address. Some items, such as dimmers will then only require one channel of control and some items will require more. There are 512 channels per DMX universe.

 

Nothing particularly difficult- It has been around a long time. Have a good read of it and if you have any specific questions pop back and I am sure many people here will be able to answer them.

 

edit to say - I was too slow and David Elsbury got there first.

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I think the problem is that everyone talks about 'DMX' as if it's some new amazing, radical, actually interesting thing - but the reality is it's what you use it FOR that is the interesting bit.

 

When they came out with D54 and AMX, it was simply a convenient way to do away with multicore cables - nobody got very excited because although the controls that used it were new, and I suppose a 'bit' radical - they just let you memorise things, and that was the clever bit. Now - the kit that gets stuck on both ends is gizmo filled and perhaps to some people exciting - and DMX takes the credit, when the reality is, it's just a bit of wire that does no more than it did when it was first brought out - apart from tiny changes that most people don't even notice. It has the real excitement potential of a bit of mic cable, or the ring main in your house. It's just becoming somehow 'magical' - when the magic is in the gadgetry on the end, and what you do with it!

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I was about to post on a similar theme to Paul; we do from time to time see people posting here who think that DMX means a certain desk, or moving lights, or some other fancy thing. In reality, it's really just a way of replacing 512 individual bits of wire with two+screen!
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I think the problem is that everyone talks about 'DMX' as if it's some new amazing, radical, actually interesting thing - but the reality is it's what you use it FOR that is the interesting bit.

 

When they came out with D54 and AMX, it was simply a convenient way to do away with multicore cables - nobody got very excited because although the controls that used it were new, and I suppose a 'bit' radical - they just let you memorise things, and that was the clever bit. Now - the kit that gets stuck on both ends is gizmo filled and perhaps to some people exciting - and DMX takes the credit, when the reality is, it's just a bit of wire that does no more than it did when it was first brought out - apart from tiny changes that most people don't even notice. It has the real excitement potential of a bit of mic cable, or the ring main in your house. It's just becoming somehow 'magical' - when the magic is in the gadgetry on the end, and what you do with it!

 

Well said. I recall being livid that it was rolled out at an affordable price just after, well a year or so after, I'd had a new space wired with several rings of multicore at a lot of money.

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Hi Ricky,

 

To be fair, DMX is actually on it's way out to a degree having been around since 1986 (ish) it's starting to become a little outdated. That is not to say that it isn't used, far from it, there are too many fixtures around for the protocol to be dropped from use. However it is not uncommon to want to control vast arrays of LEDs which eat up DMX outputs like there's no tomorrow. DMX is still the most popular protocol to talk to individual fixtures (moving lights, dimmers etc) however it is becoming increasingly common to find that the lighting desk outputs on a different format such as Artnet, MAnet, Pathport or shownet (there are others) and is then converted locally into DMX.

 

There's plenty of information out there available. Try doing a search for USITT DMX512/1990. As for training, it's really quite simple. DMX outputs packets of information many times a second. Each packet contains a value for each of the 512 channels you are able to fit on a single DMX output (also known as a universe). When setting up a DMX system you have to give each fixture a start address, this address tells the fixture what values out of the 512 it's hearing to respond to. For example, if you had a typical 24 channel dimmer with a start address of 001 it would listen to the first 24 channels of information in each packet. When you set up or patch your desk you tell it that it has 24 channels of dimmers starting at address 001 then when you put channel 1 to 100% the desk changes the value of channel 1 from 0 to 100%, your dimmers listen to the DMX and turn your light on.

 

With Moving lights it's exactly the same except that each light uses multiple DMX channels to control various features of the light such as pan, tilt, colour, gobo, focus etc. How many channels a light uses depends on what model it is and even which mode it is in. All of this information is in the manual for the light but to save us having to worry about this most lighting desks have pre made personalities for each light these are the lighting equivalent of a driver and allow the desk to give you easy access to the available features without having to worry about what channel they are on.

 

So when you're setting up a DMX system you need to plan things in order to makes sure that you're able to talk to everything without two things listening to the same information. In other words, don't set your 24 dimmers to start address address 001 and then try and set a moving light to address 002 as the mover will respond when you try and use dimmer number two. In this situation, the first address you could use for your moving light is 025 however it is OK to have gaps with empty channels, plenty of people set up their moving lights with easy to remember numbers so for a moving light that uses 16 channels of DMX you might give them addresses of 100 120 140 160 and so on making it easier to remember and saving you doing the maths every day.

 

So, you know what fixtures you're using and you've worked out what addresses you're giving them now you need to actually give them DMX. Officially USITT DMX512/1990 states that you should use a 5 pin XLR type connector although a lot of manufacturers only use 3pin XLR to keep manufacturing costs down. Either way, you need to use suitable DMX cable with the correct connector for your fixtures. Every DMX fixture has an input and output connection all you need to do is connect things together starting with the output from your desk and continuing to your first fixture then on to the second and so on until everything is connected then in the output of the last fixture you connect a terminator which is simply a connector with a resistor across pins 1 and 2. Although there is no requirement to put things in a specific order it is traditional (on a single universe system) to put your dimmers at the start of the DMX chain as if a cable fault develops this gives you a better chance of still being able to put lights on and the audience being able to see the show.

 

One thing you can't do with DMX is "Y" split it, this can cause data issues such as random flashing or movers jumping about uncontrollably. If you need to split your DMX signal then the you need to use a DMX splitter which is a device that listens to the DMX signal from the desk and repeats it across several outputs giving you the ability to send the same signal to various locations such as the dimmer room, LX bar 1,2, and 3 and maybe to the smoke machine on stage. Splitters save you having to run loads of cable all over the place, give you a bit more flexibility and allow for some things to go wrong without affecting the whole lighting rig.

 

Does that all make sense?

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Thanks for all the help. Sorry should have explained a little better the reason I am asking is because I went for a temp job last year and my lack of knowlage on DMX was the deciding factor on me not getting the job.

 

Grum, that all makes perfect sence thank you.

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  • 4 weeks later...

To be honest I'm amazed that people nowadays seem to want to do courses on subjects that are not difficult to teach yourself. I'm not blaming SE - they've discovered people are willing to pay them to deliver the material, so why not?

 

The thing is that there seems to be some growing evidence that people expect to be taught, rather than doing it themselves? I'm certain that for many people, when they go off to uni, it's a real shock to discover that they're expected to teach themselves, rather than being spoon fed it as they had at school.

 

DMX is a classic example. We're talking about a protocol first and foremost. So much info on the net and in books that if you want ultra basics it is there, and if you want to know the ins and outs of current loops from a technical perspective or the historical development and progression of the standard it's there too.

 

All the actual hardware doesn't really need hands on experience. Fault finding is probably the most difficult, but again, do you need to artificially generate a fault and then have a bunch of people try to find it? When you get your own first fault, it will be different. Did the simulation actually help?

 

The OP said they were turned down for a job because they had a lack of knowledge about DMX - seriously, for years people taught themselves the theory, read all about good and bad practice, and then when presented with it for real, it really isn't an issue. For me, the only problem with DMX control is simply the mechanical aspects of how to actually get it to where it's needed. If I need to know some deep technical data, I look it up?

 

I few weeks ago I found some people having a two hour session on barn doors! What on earth can you do with four bits of metal for two hours? Next week, we'll be training people to fit a hook clamp.

 

People seem to have this weird need to be 'trained' how to do everything, when knowing the process was enough.

 

When I was a kid, I read every book I could find on how to drive a steam locomotive. I have no idea why. When I was 12 I went to Bressingham Steam Museum, and got into the cab of the Oliver Cromwell - quite a famous engine of it's time. I asked the driver if I could put it in forward gear and open the regulator - he smiled and said, "Go Ahead" - I knew how to do it from the book, and as I appeared to know what to do - he let me. Nowadays, we'd want to go on a course!

 

 

Sorry for the grump, but it's just strange to me.

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I'm with Paul on this but with a wry smile. How many times on BR have I read 'Have you been properly trained?' when posts appear about certain subjects. RA's and ladders come to mind, but there are many other examples.

 

Edit to add. The problem is that many people will now take nothing other than a certificate of course completion as evidence of competence! Being shown how to do something or working it out for yourself, followed by years of experience is often not enough to satisfy the pen pushers!

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The problem is that many people will now take nothing other than a certificate of course completion as evidence of competence!

Brings back memories of the first job I applied for after completing my sparky apprenticeship,they asked if I had a 15th edition regs ticket,explained it was included as part as part of the college course,but no ,I had to take the course and exam.

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Ref the nod to "pen pushers"...if the pen pushers mentioned above are the insurance underwriters type bods then, seeing as how insuring you or a venue is at THEIR risk, they make the rules, which is hardly unreasonable.

 

Similarly, you would be quite astonished if some yoof tried to insure him/herself to drive a car and said that actually no, (s)he did not have a driving licence as such but then stated, "Look on the bright side, I have watched my Mum/Dad loads of times, AND, I watch "Top Gear", then quoting JC so how difficult can it be?"

 

To draw the analogy even further, a car over three years old in UK requires an MOT together with an emissions cert'. Nobody seems to moan about that sort of thing so what is the difference, really, about having certs' of competence and PAT tickets?

 

From mutterings on this forum we have learned that "tallescopes" are perfectly safe to drive around "a" stage. Little thought seems to have gone into understanding that although this notion might be true, because you have yet to have an accident, the H&S community have seen and investigated the aftermath of accidents involving tallescopes in other industries.

 

H&S is NOT attacking theatreland, it is trying to evolve solutions/guidelines/advice, call what you will, to ensure safe working practices.

 

So, rapidly getting back on topic, with ref to getting DMX training then what is the problem with that? After all we do see queries about "why does my DMX kit not work as advertised" and we see the same responses.

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