Zero88 Betapack 2 DMX Error

[Emmien]

I am trying to daisy chain two cheap LED parcans from four Zero 88 Betapacks.

 

The Betapacks have a 5 pin XLR output, so I connected a 5 pin to 3 pin XLR adapter. When I plug in the adapter, the green OK LED flashes for a second, then turns steady on, no errors and control of the lights.

As soon as I connect a cable onto the adapter, the OK light flashes, then turns off and the error indicator turns on.

 

I then thought that maybe I need to connect the cable to the RGB par can. I did that and I could control the par can but not the Betapacks. The error LED stayed on.

I have tried multiple 3 pin XLRs.

 

 

 

I am not quite sure what the problem could be. Could the betapacks be detecting that there is no DMX terminator (Which there isn't on them, but they may have an internal one) and not working?

I have thought about changing it so the DMX ran to the parcans, then to the Betapacks, but it would involve some homemade XLR-RJ45 boards and cat5.

I also thought about running 5 pin XLR and putting the adapter right up on the Parcan, then use cat5 from the parcan to the next, where there is another adapter and a short DMX cable.

 

Has anyone had this problem with these dimmers?

[Andrew C]

If I follow you correctly, I'd be looking at wiring errors. Maybe a shell on an XLR connected to pin 1, maybe a simple short.

[alistermorton]

Are the three pin cables wired correctly - you don't have the connector shields connected to the signal shield or anything like that creating an earth (hum) loop?

 

You'd probably be well advised to plug a terminator into the PAR can which is at the end of the run, too. I think but I'm not sure that the betapacks can self terminate if they don't have anything in the DMX out, but when you plug your cans in there will need to be a terminator on the last one.

[vinntec]

You need to do some problem determination to rule out what isn't causing the problem. Have you tried connecting the two daisy-chained LEDs direct to the desk (via an adapter of course) and cut out the dimmers temporarily? If that doesn't work then you know the dimmers are [probably] fine and one of the components you are using is setup incorrectly. If this does work then you know that the cabling and adapter and the LEDs appear to work OK so need to check the dimmers. The BetaPacks (II or III) are almost bullet proof reliable so I woud suspect first the cheap LEDs are wired correctly (compare what the manual says compared to the "norm" for 3-pin working), then the XLR cables, then the adapters, then the dimmers. Make sure of course you are not using crossover cables accidentally (you can continuity check these and the adapters easily with a simple multimeter).

[Emmien]

You need to do some problem determination to rule out what isn't causing the problem. Have you tried connecting the two daisy-chained LEDs direct to the desk (via an adapter of course) and cut out the dimmers temporarily? If that doesn't work then you know the dimmers are [probably] fine and one of the components you are using is setup incorrectly. If this does work then you know that the cabling and adapter and the LEDs appear to work OK so need to check the dimmers. The BetaPacks (II or III) are almost bullet proof reliable so I woud suspect first the cheap LEDs are wired correctly (compare what the manual says compared to the "norm" for 3-pin working), then the XLR cables, then the adapters, then the dimmers. Make sure of course you are not using crossover cables accidentally (you can continuity check these and the adapters easily with a simple multimeter).

 

I connected the RGB LED Parcans up directly to the desk and they work fine. They even work fine when the Betapacks are having this error. I can control the parcans, but not the dimmers.

This makes me believe that the adapter and three pin XLR cable are OK.

I tried several 3 pin XLRs. When I get a chance I will do a continuity check between the XLR shell and GND pin, but I doubt that they all have that.

 

I don't have a three pin XLR terminator, but there is a 5 pin one somewhere. I can try and make one though, if I find a suitable resistor.

 

A quick Google search shows that each Betapack 2 has self termination. If it does not detect an output, then it connects the resistor.

Termination could be the problem. I don't know how the Betapack 2 detects whether it is at the end of the line. Is it mechanical or electrical?

I think it could do something electrical, because the problem does not occur until I have the XLR cable connected. The OK light flashes when I attach the adapter, but no errors until I connect the cable.

 

Thanks for your help so far.

[alistermorton]

I haven't used them but I'd guess the betapack physically switches its terminator out by the action of the plug being inserted so when you insert the DMX out plug the line is unterminated.

[themadhippy]

the pars aren’t sending out DMX from the built in fx's thats confusing the dimmer by any chance?

[IRW]

Beta 2's do NOT self terminate, but do have the facility to terminate.

From the manual:

 

DMX Termination

Each Betapack 2 has a built in DMX termination.

It is connected by adding a short wire link between ‘EOL’ and ‘DMX-’ on the DMX Printed Circuit.

(See Diagram 5).

Connection ‘CHS’ referes to chassis and is unused

[Emmien]

I haven't used them but I'd guess the betapack physically switches its terminator out by the action of the plug being inserted so when you insert the DMX out plug the line is unterminated.

This can't be the case, because the problem does not occur when the adapter is inserted. It only happens when the cable is connected onto the adapter.

Also, IRW says that Beta 2s do not self terminate.

Dimmer 4, the last in the chain is probably has the jumper or switch that enables termination.

 

I might connect the LED parcans in between dimmer 3 and 4, so it would be like this

 

DESK --> Dimmer 1 --> Dimmer 2 --> Dimmer 3 --> LED Pars --> Dimmer 4

 

 

 

 

[alistermorton]

Ah - im sure there is a z88 unit which can terminate depending on whether the is a plug in the out hole.

 

That said - if it was working without an external terminator before it probably now has one, effectively, half way down the line. Which will not be ideal.

[Emmien]

the pars aren't sending out DMX from the built in fx's thats confusing the dimmer by any chance?

 

Nope. The problem begins even before I plug the pars in.

 

 

I have read the Zero 88 Betapack 2 manual and it does mention incorrect termination causes problems.

I might try connecting a small dimmer pack or light which does self terminate to the end of the line. Perhaps that will help.

[richardash1981]

I might try connecting a small dimmer pack or light which does self terminate to the end of the line. Perhaps that will help.

Read the post from alistermorton more carefully. He is suggesting that your 4th Betapack has been internally modified to always enable a terminator. If this is the case, you will need to either remove the modification, or take that pack off the system, or move it to the end of the chain, in order to get rid of the incorrect termination half way down the line.

 

Having too many terminations will over-load the line (amongst other things) which could certainly cause the betapacks to loose DMX signal.

 

[timsabre]

Adding or removing termination will not cause a fault like this. There must be another fault in the DMX line.

 

I would meter through the DMX pins from one end to the other with all the dimmers connected. That should show something up. Also try a different DMX source.

[ianknight]

From experience, if the Beta 2 is indicating a DMX Error then there's a cable issue - I know it sounds daft but check the adaptor you're using. If it's a homebrew cable adaptor then it's entirely possible that pins 2 & 3 are crossed - the pins in XLR 3's don't follow 1 - 2 - 3 in a 3pin XLR but in fact 1 - 3 - 2.

 

Some installers did actually install internal terminators, usually where they felt there was a likelihood of an external terminator going missing. The simple way to check if Rack 4 is terminated is plug your RGB cans on to the DMX run feeding it and see if the problem persists.

 

It's not going to be anything horribly technical - the Beta 2 isn't that complex ;)

[timsabre]

The simple way to check if Rack 4 is terminated is plug your RGB cans on to the DMX run feeding it and see if the problem persists.

 

Wouldn't make any difference, the terminator doesn't "stop" the signal. DMX will usually continue to work with 2 or 3 terminators on the line or no termination at all.

The only way to tell is to meter resistance across pins 2 and 3 (with power off and the DMX source disconnected).

 

But the whole termination thing is irrelevant, the actual problem is elsewhere.