Moving Light Problem.

[paulears]

ROAD - I'm very sorry - but you are talking complete Bu***hit!

 

Terminating DMX (as has been done to death on this and loads of other forums) is vital for stable operation. Just because you haven't had any problems, this is not a basis to dish out inaccurate info as fact!

 

The whole design philosophy of DMX requires a terminated line - it's inblack and white in the spec. Everyone builds kit to match the spec. It only takes one device to suddenly send the system into meltdown. And the first time you've experienced it, I guarantee you will never, ever, do it again. The problems unterminated DMX causes are major headaches - odd movers suddenly doing their own thing, smoke machines suddenly squirting - daft things like that. Very often the 'culprit' device carries on working fine.

 

 

There are many people on the blue room list who are very new to all this - advice like yours is confusing. The spec says terminate - so terminate.

[gareth]

ROAD - I'm very sorry - but you are talking complete Bu***hit!

 

Terminating DMX (as has been done to death on this and loads of other forums) is vital for stable operation. Just because you haven't had any problems, this is not a basis to dish out inaccurate info as fact!

Paul's absolutely right. There are sundry other topics on the forum that deal with the subject of DMX termination - a few minutes with the Search function (top-right of the page) will yield many results. So please let's keep this topic focussed on the subject in hand, and not let it deviate into yet another discussion on the merits or otherwise of DMX termination.

[G2000]

ROAD - I'm very sorry - but you are talking complete Bu***hit!

 

Firstly I don't think there is any need to use such negative language in an open forum.

 

Secondly I agree with road. As someone who has toured for a number of years with large shows with moving light rigs often containing over 100 units and have never once terminated a rig and never once had a problem. I watch rigs go out on the road for months at a time with technicians who have years of experience, without termination. I will always carry termination plugs for the day where it may be necessary but so far over the last 6 years that day has not yet come.

 

Just because you haven't had any problems, this is not a basis to dish out inaccurate info as fact!

 

I don't think road was dishing out any facts, only his opinion based on his experience just as I have above.

 

There are many people on the blue room list who are very new to all this - advice like yours is confusing. The spec says terminate - so terminate.

 

True, however things are not always black and white, let people try it out for themselves. This is not supposed to be a 'technical bible' where people can come to find a definitive answer. All advice is valuable if it is based on anothers experience.

[paulears]

first of all terminating DMX is a load of bull whip

<{POST_SNAPBACK}>

 

I don't think it is negative at all.

 

You can choose to use DMX however you like - your call. However, most blue-room members like to think that advice should be based on 'best practice'.

 

Unterminated DMX may work fine - but the emphasis should be on the word may.

 

As for a technical bible - I'd like to think the advice and comment given by members is as accurate and valuable as it can be. There are plenty of technical sites where absolute rubbish gets posted. It doesn't happen here - people soon post 'proper' answers.

 

I may have run a few unterminated DMX lines myself without problems - BUT, from time to time all hell breaks loose and these sort of problems are the ones that people then spend ages trying to sort out. Bad practice should be discouraged, best practice encouraged.

 

One point - if you always carry terminators, why not fit them. You'd look pretty stupid mid-show when the movers throw a wobbly if you actually had the gadget that would have cured it in the toolbox, but didn't bother. It's always the last show you do that gets you the next.

[peter]

The way I see it, if you have problems, and your line is terminated, you've got one less thing to check.

 

But please, lets keep this on topic. As has already been said, the discussions about termination have been held elsewhere - do a quick search (above, to the right) to find them.

[danburns]

I notice that the OP says his DMX run goes Desks > Demux > Movers.

Does the demux have internal termination? If it's switched on, then surely nothing will go past. It's worth a check. Also, do the movers receive DMX if he runs the cable from desk > movers bypassing the demux. If this works, what happens if the demux goes at the end of the DMX chain?

 

Dan

[mostlyharmless]

I notice that the OP says his DMX run goes Desks > Demux > Movers.

Does the demux have internal termination? If it's switched on, then surely nothing will go past. It's worth a check. Also, do the movers receive DMX if he runs the cable from desk > movers bypassing the demux. If this works, what happens if the demux goes at the end of the DMX chain?

 

Dan

<{POST_SNAPBACK}>

We've tryed carrying the desk all the way to the stage and just going straght from that into one of the movers, and still no signal (I think)

 

I went to the hire comapny and got another 5 pin to 3 pin converter, but this time the other way around I think. The guy said I souldnt have been able to phyically conect them together with the other lead without going through the output socket as an input :(

 

Ill have a look on monday and see if this was the problem, I think its also worth a look to check I was using the right cables, will it not work if I accidently used a mic cable instead of a DMX one by accident?

[peter]

If you'd used mic cable you probably would still get some signal through to the movers. Its most likely to be the fact that your jumper is/was incorrect.

[mostlyharmless]

If you'd used mic cable you probably would still get some signal through to the movers.  Its most likely to be the fact that your jumper is/was incorrect.

<{POST_SNAPBACK}>

Well I cant get in until monday to try and sort it, so hopefully this new lead will sort it..

[gareth]

You're on the right track with linking the desk straight to the fixture as directly as possible - desk > 5-3 jumper > short cable > fixture. Remove as many factors as possible from the equation, see if it works, and if it does re-introduce the factors one by one until it falls over - and there's your problem!

 

Regarding mic cable - yes, it'll work over short runs, but it's not ideal.

 

I'm not quite sure what you point is regarding the gender of the 5-3 convertor - the output of the desk will be on a female XLR, so the only convertor that would've fitted would've been a 5-pin male to 3-pin female. Unless, of course, you had a jumper that was also a gender-changer at the same time ....