A quick (and easy) guide to DMX

Setting units in Master/Slave link mode

Setting all Dipswitches 1 through to 9 OFF will put the unit in MASTER mode when linking units together, this causes the unit to transmit data to any SLAVES which may be connected. Units are put into SLAVE mode by setting Dipswitch 1 ON and 2 through to 9 in the OFF position.

DMX Address setting

Each of the Dipswitch has an associated weighting, meaning each numbered switch is worth a certain value. This is represented mathematically by the Formula 2^(X-1)=weighting (where X is the number of the switch)

(This ^ symbol indicates that the proceding number is the power to which the number before is raised to. ie 2^2 = 2² = 2x2 = 4 and 2^3=2³ = 2x2x2 = 8)

Example:-

Switch 2 has a waiting of:- 2^(X-1) (Where X is 1 for switch 1)

2^0(*)= 1

* (Anything raised to the power of Zero is 1)

Similiarly Switch 3 has a waiting of:- 2^(3-1) (where X is 3 for switch 3)

2^2= 2x2 = 4

The value of each switch that is set in the ON position accumulates. For the Picture above switches 1-5 are OFF and 6-10 are ON. This is best displayed in a table as shown below.

Dipswitch 1 2 3 4 5 6 7 8 9
Weighting Calculation 2^0 2^1 2^2 2^3 2^4 2^5 2^6 2^7 2^8
Weighting 1 2 4 8 16 32 64 128 256
ON = 1 OFF=0 0 0 0 0 0 1 1 1 1
Values 0 0 0 0 0 32 64 128 256
Total 32+64+128+256 = 480

Therefore a Unit with the Dip-swtich configuration as shown in the picture above will begin recieving DMX512 data at channel 480.

It is important to remember that the address set by the Dip-switches is the DMX base address, this means that the unit will start reading data from this address and procede to read remaining channel functions on consecutive addresses.

For instance if a Scan (Requiring 4 DMX channels), dip-switch settings were set as shown in the picture above channel 480 would control its PAN movement, 481 would control its TILT movement, 482 the COLOUR wheel position and 483 the selection of the GOBO.

Hopefully this helps a little

As stupid as this sounds, but I follow that. Cheers, I never understood other people directions on the switches

Thanks Andy - Very Useful

Im about to be getting into DMX a bit further than I have previously (in the next few days in fact).

The above shows how DMX Channels are allocated. Is that per "Effect" or per "Type of effect"?

EG: Using the above example of Channel 480, lets say that you had ONE scanner effect requiring four channels of data (EG: One for Pan, one for tilt, one for colour, one for gobo choice). Channel 480 is just "there" (you dont send data to it effectively), 481 would be Pan, 482, would be Tilt, 483 colour choice, 484 gobo choice.

OK..I understand that - it was very well explained using the Binary Abacus style above.

Now, if I added a second scanner (another identical one to the one above), would I simply Slave it up to the first unit, or would I set the DMX channel of the second unit to the same channel (480) as the first, so it copies all the movements/colour/gobo changes of the first, or simply through it into Slave mode and daisy-chain it from the first, or...would I give it its own DMX address eg: 485 (with 481,482,483,484...for pan,tilt, etc..) (next spare addresses) or simply 300 (or any other spare address with the next 4 channels for pan/tilt etc.)...

Also, as far as setting/programming pans/tilts/gobos etc...is this done by "firing" a value between 0 and 128, (or 256, or 512) from the controller to a particular channel? EG: If Channel 484 is colour...and your unit offers 10 colours, and the DMX controller slider offers a range of 0~255, would value 0~25 make the unit change to colour 1, values 26~50 change to colour 2, 50~75 = colour 4 etc..etc...?

Hmmmmm

Anyone selling any front screens?

they said intelligent lighting, they failed to say thick as pig **** dj

Got I feel so thick, but then again I just chain them all together and hit the sound to light switch, works very well.

Darren

You can play with the "addressing" on light screens too...

When I used to run several light screens, instead of just the four that I have now, I used to use a channel reverser.

It was simply one of those little metal boxes with 4 bulgin sockets on it, but I reversed the channel wiring on two of the sockets. So channel 4 was where Channel 1 should be, channel 3 was channel 2, channel 2 was 3, and 4 was 1.

It made some interesting effects and enabled me to adjust the lighting a little, mid-show (with that particular controller "OFF" for a few seconds, during the change).

For example:

If Channel 1 on all my lightscreens were RED, Channel 2: Yellow, Channel 3: Green, Channel 4: Blue, then I could either have all the RED's on together, or by moving the bulgin plug for the top half of the screens into the reverse-wired socket in one place (the little black box) then I would have the Red's on with the Blues etc...etc...

Not as much fun as DMX by the sounds of it though...

Shall try and answer a couple of questions.

yeh how does that work.

how can you invert pan and tilt in dmx mode if you olny have one set of dipswitches, do lighting effects have two sets, one for dmx and one for inversion etc????????

Daniel

Not doing this stuff for discos mainly for theatre. it depends on the light units themselves, some of them have a feature that if they are slaved off another unit they an be set to do the opposite of the master, but as for not running them in master or slave i imagine some units would have the ability to reverse pan/tilt from what they are recieving from the controllers. i know from usin Mac 500's and 250's it's a lot easier to have them all on seperate DMX patches. But that's my personal opinion.

Ste

There is no standard to the number of channels a light will use.

You may also find this helpfull:

Abstract CED and 3CE effects use 4 channels however the 1CE effects use only 2.
Martin DJ rance differ through the rance from 2ch to 6ch.
Where as moving heas can have anywhere between 8ch to 64 for the big ones !!!

As for DMX code, here is how i explain it to users...
Image the DMX code being a train with the engine being the controller and start of the DMX Code. This train has 512 carriages, and each can carry between 0 and 255, and it runs in a continuous circle.
So for this example, our light has a base address of 20 and uses 4 channels. Along comes the train and the light will count the carriages... When it gets to 20 it then "counts" the contents in carriages 20,21,22, and 23. it then uses these values to produce the effects.

A common misconception that i have been asked many time is: "What address is the controller?" It doesnt have an address. It will transmit continously so it doesn't need an address. How ever the more expensive controllers can receive DMX through another socket.

So, How do i know where to start?
Firstly you need to work out how many channels all your effects use, an how many effects you have. e.g. 4x Abstract VR8 Scanners each have 4 channels = 16 DMX channels. So you then need a controller capable of at least 16 channels.

So what channels do i need to setup on each light?
Well, Each of light need only the base address configured. Then the light knows how many channels after the base address to look at.

I hope this clears things up a little for those of you whom are confused about DMX!

ctrl + C ctrl + V , the quickest way to post

Did anyone mention Terminators?

No not the Arnold kind

Bacially most lights have a dip switch for termination, older effects may not, so the last light in the run should be terminated either by a dip or a dongle.

But, and there is always a but... for small light setups and some controllers, they do not require a terminator, but if you have the feature on your last in the chain effect, then better to use it.

(bacially it's just a resitor which lets the controller know it's the end of the line)

Also for reversing of Pan/tilt using DMX,,, you can simply address the light to it's own dmx address and then simply program the pan tilt to do what ever you want, whenever you want. It may take time to program a full show, but it's worth it, then by using the copy command on some controllers you can then copy the program to another store point and edit it so you can save a little bit of time by copying some shows and editing key points.

First points,

Their is no such thing as "master" or "slave" in DMX.

Each fixture is its own entity, totally equal. When using master and slave features on "DMX" lamps all you are actually doing is using the cabled connection to transfer MANUFACTURER SPECIFIC information from one fixture (Master) to all the other Slave units.

A good example is for yrs MARTIN used their own protocol to control units (which worked very effectivly). However all new MARTIN fixtures are now true DMX, however they still do encorparate "Manufacturer specific standalone programs" on lower cost models to date.

This signal is not DMX as DMX is industry standard and therefore all manufacturers units would respond, which im sure others have experienced. They certainly wont.

Termination is not to tell the controller its the end of the line but to prevent signal reflection, similar to basics with BNC computer networking and SCSI termination. It is to prevent corrupt data moving back down the line.

One quick question about DMX - Consider this scenario

I have two scanners, but they don't have the facility to invert pan and tilt on the second one, so I've assigned them to two seperate addresses.

I want them both doing different things, but at the same time. How do I go about inputting that into the controller? From how I see it at the moment, while I'm programming one of them, the other will presumably sit in blackout. Is it possible to go back to that sequence and add the other "layer" on top of it, or do you program it as a seperate show and run both as once... or....?

'm new to DMX, so bear with me if it's a silly question! I've only had the experience of the basic soundlab controller you see, and to me there never seemed the facility to create multiple movements across different units, everything had to be doing the same thing at the same time.

Set the DMX values on your controller for 1, then for t'other. Then store the scene..

Clear as mud?

I've found the easiest way of achieving reversed movement on one or more axis whilst still copying is to set up the 2 channels for each head (or group of heads) and program 1 with what you want entirely. Then copy the whole channel to the second one and go through each scene changing the value on the DMX channel you want reversed.

There's also the option of doing the hardware and reversing the wires in the unit for a permanent fix. you need to remember to reposition end stops for mirrors if you do this as they'll try to turn the wrong way from the existing stops when they zero on startup

At last DMX explained

To all the above

I thought that I'd understood the basics of DMX as I read through this thread until I found this chart for a DMX lighting effect.



If a lighting effect needs 3 Channels and you make the the channels 480, 481 and 482, how would the lights work if the above chart says, for example, that for the purple hand, it has to be between channel 140-149, or am I being a complete div and missing something.

To all Moderators - If I am being a complete div, please delete my post IMMEDIATELY to prevent riducle from fellow members

You're not being a complete div Ben, DMX is one of those things that just suddenly clicks in your mind but at first is totally baffling.

I think where you are getting confused is with the channel/addressing and contol values.

481, 482 & 483 are not channels, they are control values.

If you set the start address of the fixture to say 1 or 5 or 9 assuming you have a 4 channel controller, then you send a value between 130 & 139 to chanel 1, you will get a red heart.

If you send a value of 11 to the next channel above the starting address then the shutter will operate slowly, a value of 100 will make the shutter operate at medium speed, and a value of 255 will make it operate at its fastest speed.

If you send a value of 2 to the next channel ie: 2 above the starting address, then the reflector will spin fast. Send a value of 99 and it will spin slow.

Remember, the starting addresses of your fixtures is determined by how many channels your controller has.

Just out of curiosity, what does DMX stand for???

Digital MultipleX

Here's where I join the ranks of idiots!
I ave just got a dmx strobe with a trancesion 6 channel contro;;er...there are 6 channels and a master.
If I want the strobe to operate on channels 1 ,,,what do I set the dipswitch to?
I also have a couple of moving heads...can I use the remaining channels to work these. If so, how do I get numbers 2 3 4 and 5 in dipswitch language.
I also note there are ....oh lets do this one first

If I have a moving head...I want channel 1 to work the spin, channel 2 to tilt, channel 3 to gobo change. What would the dipswitch setting be...1 2 3? or just 1?

If you want each DMX fixture to work independently then you have to assign a different ID to each, but you also have to allow for each fixture's channels, thus, if you have a 2 channel strobe and you assign it to DMX ID1 then your next feature will start at ID3. If this was a 4 channel fixture then your next fixture would be ID7.

as to your question as to the dip switches:

1 = pin 1 on
2 = pin 2 on
3 = pin 1+2 on
4 = pin 3 on
5 = pin 3+1 on
6 = pin 3+2 on
7 = pin 3+2+1 on
8 = pin 4 on

and so on.

think i'll read this thread again, and again then print it and read it in the morning.

however am i right in saying the featured gobo/DMX guide is Courtesy of KAM?

Got you! So the fixture automatically assigns its channels in numeric order? So a six channel controller can take a two channel strobe on channels 1 &2. If I have a four channel unit I set that to channel 3 and that automatically also takes up channels 4 5 6? I think I got it! Eureka! Don't tell me I'm wrong :o(

Many many thanks!!!

OK got the velleman k8062, stuck it together, downloaded freestyler and tried the supplied software, not a sausage. The light on the box (power led) is on but the dmx led is not. No smells or smoke/flames etc coming out of the unit. I am using vista as my os, any clues ???????

Did you get it sorted?
Is the Velleman showing up in device manager (as either a HID usb device, or a USB device)?

Jim

Use the supplied DMX software that came with the 8062. This is very crude, but does work. I suggest trying it with 1 fixture with address 1.

Once you can tweak a few channels, and see the results, then move onto freestyler knowing the hardware is ok.

Jason

Hi, all. Now I have read the posts on this subject, Im happy about giving each unit its own address and counting how many channels it takes up. I have recently come across a Botex dc 1216 controller, I have daisy chained some Show Tec LED par cans (X3) some Scanic Scanner 250's (X2) and a Scanic Ray gun 100 (red and green laser). I have followed the advice given on here but the whole thing does not respond to anything I do, Im guessing that the unit may have some scenes etc still in its memory and because my lights are different it just does what it wants, apart from mindless violence against the thing, has anyone got any tips for me, apart from a college course

Rather than link everything up, try just one fixture.
Set the address of that fixture to 1 and see if the controller works with it.
Some controller and some fixtures sometimes have the hot and cold (+ and -) the opposite way round.
Check the pin assignments on the controller and the ones on the fixture agree.
Are you also making sure you are using a suitable lead and not an unbalanced mic lead.

Jim

Many thanks Jim, I will be all over it like a tramp on chips today, I will not be denied !!!!!!!!!!!

Hi Mick, thanks for the PM.
I thought I would reply on the forum for other to see though.

You say that all your cables where bought as 'mic' cables and you will go and get DMX cables.

You need to check the 'mic' cables, as if they are 'balanced' they will be ok for DMX.

The XLR will have numbers on the pins, the connections for DMX are :-

1 - Screen
2 - Data -ve (cold)
3 - Data +ve (hot)

If it is a unbalance mic cable then it will be connected as follows :-

1- Screen
2- +ve (signal)
3- Not used or connected to pin 1

A balanced mic/audio cable is connected as :-

1- Screen
2- In Phase/ +ve (hot)
3- Out of Phase / -ve (cold)

As you can see pins 2 and 3 have different descriptions for DMX and audio but that doesn't really matter, the point being that pin 2 is connected to pin 2, and pin 3 is connected to pin 3.

In the unbalanced mic cable pin 3 will either be not connected at all, or will be shorted out to pin 1.

If your XLRs are the typre that can be taken apart, you can just open up the shell and have a look at the connections to see what is happening to pin 3. If not you will need to meter the cable out.

I hope this helps.
Let us know how you get on.

Jim

Cheers Jim, checked the connectors and they are connected as you describe, so I now deduce, (from your tips and some youtube vids on DMX), I have a problem with the signal getting from the desk to my lights, they don't respond to any slider movements at all. I will now get more coffee and go again, cheers again Jim.

Try swapping pin 1 and 2 around on one of your cables, then try that cable.

Jim

OK I now have a result and a garage thats like Blackpool illuminations, the problem was simple............. On the Botex desk there is an unmarked switch, this is the polarity switch and described in the manual. As the Meerkat said Sipulsk. Thank you Jim for your advice as it leant me towards a comms issue from desk to lights. I can now practice some scenes and hopefully build some decent results. I like this DMX stuff now a slight break from my 9 to 5 job.......... http://www.youtube.com/watch?v=pKe3c75mH5c...feature=related

Many thanks again.

The switch has the same affect as crossing pins 2 and 3.

The next step is to add one fixture at a time to make sure they all behave as you expect them to behave.
Dont forget that if you had multiple fixtures of the same type (ie your two Scanic Scanner 250's) and you want them to operate identical to each other, you can assign the same DMX address to them both.
Most scanners also have switches to invert the pan or tilt so you can have the same signal going to them but have them running as mirror images of each other, this is useful if you have them at oposite ends of your truss for example.

One final thing, don't forget about using a terminator at the end of your DMX chain.

Jim

Everything is working great now Jim, I am not using a terminator, is it important ?

A terminator prevents spurious signal in the DMX signal.
It is something that you SHOULD have.
You may not have a problem, but for the sake of a couple of quid they are worth having.

Jim

Roger that, will put it on my list now I don't have to buy cables ;) Many thanks.

I didn't spot it in the thread (apologies if I missed it), but a very useful tool to have when using dipswitches is a dip switch calculator

I will post a link here (it's not commercial) which I think you will find really handy. http://www.sabretechnology.co.uk/calc.asp

Freestyler has one built in

For iPhone users it gets even better - download 'Lampy'

Hope this makes life easier chaps !

Decimal is for wimps... Real Men know Binary!!



Actually, one strong selling point on ADJ par cans is the rear 7 seg LED display and push buttons. Setting DMX channel/mode, or simply the static colour does not require a manual - just press "MODE" a few times.

You just need the manual to understand the LED panel in its ownright though!

Na, only a few modes, and I mainly run static (CL0..CL7), or sound to light (with others being slaves with "SLA" set as mode).
Only need to read the manual to know which DMX mode to use for simple RGB.
I have a 6 slider DMX controller for the Pars, so set them Channel 1 and Channel 4 alternate, so controll all lights without messing with controller modes.

I remember learning Hex when I was about 12, and was programming assembler. Maths teacher thought she would make an example of me (as I was and still are at math).. and asked me to add a few numbers and give the answer in hex..
No problemo :-) She got her own back the week after with factoring :-(


I have an aversion to manuals, if its not easy to follow - I really struggle to understand the manual. One reason I'm grateful to Alex for helping me out with Joomla - info overload when I read various sites!

Anyone got the faintest idea what this guy is on about ?