ld90 and dmx

[themadhippy]

ok am I missing something here? In an effort to drag our venue into the 20th century (yes I know its the 21st ) im trying to get our ld90 dimmer pack to work with DMX instead of d54, DMX appears to be getting to the dimmers as the mux good led lights up,ive changed the mux input to DMX,the desk (strand mx) output to DMX and tried moving the terminator links to all positions without any luck.The DMX data is ok as it works fine on the de-mux that controls 4 analogue packs,but regardless of what way I wire things the ld90 dont want to know,restoring it back to d54 and everything works fine, so what am I doing wrong? if all else fails im tempted to use the anolouge inputs on the ld90 from the de-mux,olny problem is were to find suitable conectors?

[Don Allen]

D54 is a Strand analogue multiplexing protocol released in 1983. Your ld90 is indicating a multiplexed input on it's status indicator but it is not valid data.

 

Do a search on DMX to D54 converters to find out what you need to interface your ld90 to your DMX stream.

 

I have a copy of Control Systems for Live Entertainment by John Huntington which is a handy reference to some of the many protocols that exist in lighting.

[themadhippy]

according to the ld90 manual and the menus the dimmers will accept DMX,along with d54, smx and anolouge so no need for any convertors,unless of course the line "optional extra" has been omited from the manual

[sparkyweb]

according to the ld90 manual and the menus the dimmers will accept DMX,along with d54, smx and anolouge so no need for any convertors,unless of course the line "optional extra" has been omited from the manual

All you should need to do is change the mux input on the LD90, mux output on the MX (don't forget if you reset the MX to default it restores the desk output to D54) and change the wiring point on the LD90.

 

Think that was all you needed to do, its been a while since I have played with LD90's, if you still have problems I'll go and get the service manual out.

 

Mark

 

- Edit -

OK just chequed my manual, make sure the wiring is as follows:

All connections are on PL15

Pin 1 = DMX Screen

Pin 2 = DMX Data -

Pin 3 = DMX Data +

 

(FYI Pin 4 is D54 signal and Pin 5 is D54 ground)

 

So you will need to change the wiring inside the dimmer, don't do this live. Be careful of those fiddly little orange connectors, Ive seen the heads on the threads be stripped before.

[Liam FitzG]

The usual warnings ... make sure you are happy to carry out the tasks involved and are competent in the relevant areas, and that all the power is off before opening any part of the dimmer.

The LD90 Defiantly accepts DMX with no optional extras. The only thing which you will require is one of the plug in terminal connectors which would have originally come with the dimmer. They are an orange 90deg plug with screw terminals down one side and a connector down the other side to suit the MUX A or MUX B position on the rear of the processor (can be labelled PL15 and PL14 respectively). Note this is a different set of terminals to the D54 ones.

The pin outs are the same as a XLR connector (ie one = Ground {screen} two = DMX data - and three = DMX data +, pins four and five are left unused. The terminations for MUX A and MUX B are identical. The termination link for MUX A is LK5, and for MUX B is LK4, the jumper should be across pins one and two on all the racks (unterminated) except the last one, which should be terminated by putting the jumper across pins two and three.

Things to check, set input protocol to DMX, set the start address, and make sure it is looking at the MUX A or B input depending on which you wired it into; and should it not work, a common reason when you have had the processor out is that the signal ribbon cables going down to the power blocks can be not home on the connectors. The ribbon cables are rarely long enough to take the processor out with them still connected so when it is fully back in place make sure the ribbon cables are pushed fully home.

Hope this helps for further information check out the "Control Signal Connections" section of the User Manual - Page 21.

 

Liam

 

....Must learn to type faster! (and possibly be less verbose!)

[themadhippy]

cheers for the pointers,having spent another couple of hours trying every combination of wiring/termination the olny thing I can think of is the DMX input isn't working so for my next trick im going to try the anolouge inputs,I hope they work

[Kazeja]

Hello.

 

I have known the Mux OK LED to come on with one leg of DMX missing, but in that case the dimmers behaved erratically as opposed to not at all.

 

Sorry to go back to really basic basics, but misunderstanding pin numbers and polarities often prove to be the root of the problem. The following is not meant to insult your intelligence but at least I'll have a better understanding in my mind of what you have done and that the basics have been checked.

 

With the orange LD90 connector disconnected from the rack and in front of you, holes facing left, screw terminals face up and wires coming in from the right, furthest away from you is screen which should go to pin 1 on the XLR.

Next one towards you is DMX- which should go to pin 2 on the XLR. The middle one is DMX+ which should go to pin 3 on the XLR. Not knowing cable lengths, Have you checked for continuity between the above connection points?

 

If continuity is OK (and correct) connect the cable to the MX and with a voltmeter set to DC, what voltage readings do you get between Screen and DMX-, and between Screen and DMX+ and between DMX- and DMX+?

 

Once these are known we will have a better understanding of where the potential problem lies.

[strand600X]

I could be wrong (it's a very long time since I used ld90's) but is there not a menu setting on the front panel to tell it to accept the DMX rather than any other input

Sorry if I'm wrong. We use ETC sensor and would gladly go back to LD90's any day.

:)

Baz

Opera North

[sparkyweb]

yes there is, I can't remember how to get to it though.

I can find out if required

[themadhippy]

Sorry to go back to really basic basics, but misunderstanding pin numbers and polarities often prove to be the root of the problem.

no problem,ive checked and double checked the connections,even reversing + and - just incase,selected mux a input for DMX(mux b isnt fitted) all without any luck.To avoid any more naughty words ive wired to the anolouge inputs from the d-mux,maybe not the neatest of soloutions but it works and avoids an ld90 from being throwen through the control room window