Positive/Negative Polarity

[si_cole]

Hi,

 

I have a number of Betapack dimmer racks (I know these are DMX but occasionally I am forced to use analogue too!) and zero88 desks which work fine. However, when going to other venues and using a mixture of items (i.e. use my racks with someone elses lighting desk), I am aware that the lighting desk is of negative output rather than positive. I only know this from speaking to various people inside the theatre.

 

So ... question is ...... how do I know what polarity the lighting desk uses?

 

Thanks ;)

[Mars]

As far as I know, Zero88 uses positive voltages to control the (analogue) dimmerpacks. However, there are 'negative-kits' to provide control to... emm... other brands. It seems unlikely that both desk and dimmers transform the positive logic to negative.

But to be sure, just measure it. Otherwise, you can also apply a Demux48 when using DMX. All your questions concerning Zero88 equipment will be kindly answered on Zero88's website (that will be www.zer... guess).

[Andrew C]

No, I think the question is "Does this desk output + or - , and can I use my racks?" Most use +ve, Strand used to use -ve. It's not too easy to measure as the pin allocation of the same connectors is different depending on the manufacturer. Instruction book or web-site would be the best bet. Failing that, check the polatity of each pin in relation to the others with a multimeter, if one is low and the rest high its +ve, or visa-versa. Good luck!

[James]

I thought some Betapacks at least auto-sensed. Is this true for all versions - as in if they are DMX as well what is the chance that they do?

 

James

[si_cole]

As far as I am aware, the betapacks don't auto-sense but they have the option of switching polarity which is handy providing you know what the polarity is in the first place :( .

 

An interesting aside to this question is the fact that some desks which seemingly would be +ve, could have a -ve card in them so the only way to check thoroughly would be the multimeter way.

 

Si

[James]

An interesting aside to this question is the fact that some desks which seemingly would be +ve, could have a -ve card in them so the only way to check thoroughly would be the multimeter way.

and of course if you know that little about the desk there is also the possibility that it could be wired to pulsar protocol, or something more bizzare and illogical.

 

James

[Eric]

OK first both the Mk1 and Mk2 Betapack are auto sensing on the analogue control input. They will respond to both a positive or a negative control with out having to do anything to the pack.

Some of the above posts mention switching polarity. The switch part is only for the phantom supply out of the dimmer used to power manual desk. The LED on the front of the pack will indicate what this is set to. Red is positive and green is negative.

Please note that if you have a MK1 Betapacks with a DMX card fitted you can't change the supply polarity to negative, plus the pack will not be able to use a negative control signal.

MK2 do not have this problem.

 

Ok as to the desk. As standard our analogue products are all positive outputs. But again as mentioned we do manufacture inverter cards to make them negative.

Only the Sirius 24/48, XL, XLS and Demux 48 have the capability of having these cards fitted internally.

Other than using a multimeter (or simular testing device) there is no way to tell if a card has been fitted with out opening them.

For the new products we do an external inverter card.

 

Then of course as mentioned you need to watch out for pulsar as they use a different wiring configurtation to both us and strand