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Technical Help
These are a few questions and answers we have provided
to help out. If you have any other questions, don't
hesitate to email us for an answer.
Colour scroller questions:
Q: Why doesn't the Colourset range of
scrollers talk DMX-512 directly?
A: The Colourset scrollers use it's own proprietary
protocol to transfer data from the power supply to the scrollers. The power
supply interprets the DMX-512 control signal. There's a couple of reasons why
we still use Colourset protocol for the wiring to the scrollers;
1/Colourset scrollers were being made
before DMX-512 was settled on as a standard, and in the interests of making
all Colourset products compatible, Colourset protocol is still used. If you
hire more Colourset products for a show, you're sure they'll work with your
existing scrollers.
2/Colourset protocol operates at a lower
frequency than DMX-512, therefore meaning that the cabling used becomes much
cheaper, there's no need for signal line termination, and the cabling is
much less prone to interference
Q: Why does the manual for my scroller
recommend to use a particular type of tape to join my gel strings with, won't
any tape do?
A: Um, No. Some tapes loose their adhesive
properties when they get hot, and can cause a real mess when they cool down.
If sticky patches are left on the gel string or rollers they can make the
scroller run really noisily, or gum it up altogether. Best stick to the recommended
tape.
Using a strip of gaff tape to make frame
markers in Colourset scrollers is also a bad idea, as it can make the rollers
run very unevenly, and can jam in the frame position sensor, possibly damaging
it.
Q: Sometimes when I run my scrollers on another
type of desk they jitter and sometimes head off in the wrong direction.
A: We've found that some desks can produce
"weird" DMX-512. This odd timing can confuse the Colourset power
supply (and other DMX-512 equipment) . We have a new version of the power
supply software available that deals with this issue, however, it will only
work in the newer version of the power supply circuit board. If you are having
a problem with this, please contact us , and if your power supply is still
under warranty, we can send out a new MCU chip for the power supply, (or
install it here at our factory). If your power supply is out of warranty, then
please contact us about a
replacement MCU chip (and PCB if necessary ).
Note this update is only required if you are
actually having a problem , or if your Colourset system is available for hire.
(and may end up being used on an "odd" desk)
Q: My lighting desk has a function where I
tell it what channel a scroller is attached to , and how many colours are loaded
in it. When running a show I simple tell the desk what colour I want, and it's
supposed to bring up the colour I want. Sometimes it works, but sometimes it
goes to half/odd colours.
A: Functions like this depend on the desk
assuming a lot about the condition of the gel in the scroller.
Using thicker gels or a combination of gel
types in a single scroll and as darker colours deform in heat can
change the way the scroll rolls onto the roller, These variations change the
effective distance for the scroller to go from one frame to another.
If the desk has decided that the scroller must
move 197 DMX units to jump to the required colour, and that colour isn't
really there , you'll end up with a half colour.
The Colourset scrollers can correct themselves
using their frame position markers when the scrollers are running in
"full frame mode" i.e.. speed control channel set to above
"0" (power supply DMX "start" ) , and scroller DMX
channels used normally. If the Colourset power supply is operating in the
DMX tracking mode (speed control set to "0") then it can only
obediently follow where the desk is telling it to go.
If you decide to use this type of
scroller control, then read the instructions carefully (sometimes it is
suggested that these functions will only work on scrollers made by the same
manufacturer)
Q: How many Colourset Scroller channels can
each power supply provide?
A: The Colourset series 1 allows 24 scroller
channels , whereas the series 2 allows 99 scroller channels per power supply.
If you need more channels, use additional power supplies (each of which can
supply power to 24 scrollers).
Q: Why does the Colourtec manual recommend
using specific types of gels in Colourtec scrolls?
A: There are a few reasons
why:
- Quieter operation
- Longer scroll life
- Accurate colour positioning
- Dark colours are less likely to warp when
used for long periods
- Faster colour changes
Colour filter questions:
Q: What's the difference between Dichroic,
colour glass and normal lighting Gels ?
A: 1/ Dichroic colour
filters offer longest life, purest colours, and the best transmission
efficiency, however, they tend to be a bit more expensive , and exhibit a
colour shift if light travels through the filter off axis. This colour
variation can be used to great effect , or it can be masked by using a
directional grille on the filter if the fixture has a wide spill angle.
2/
Colour glass filters offer long life and clean colours that are fade
resistant. They are available in a range of soft colours that work well to
soften interior lighting, and also deep rich colours. They require protection
from sudden temperature changes, and are not suitable for use in outdoor
fixtures unless they're fully protected from the weather.
3/ Theatrical lighting gels
come in a very wide range of colours, but can fade and warp over time.
Theatrical colouring gels should only be used in lighting fixtures designed specifically
for the task, as using them on other fixtures can quickly bleach or burn holes
through them. However they can be used very successfully to tint fluorescent
tubes.
DMX product questions:
Q: Our theatre production / museum/
tradeshow/theme park needs a DMX controlled device - can you make us a DMX receiver
for it?
A: Sure , contact
us for a quote, we've built custom DMX equipment for very specific tasks ,
where "off the shelf" systems were simple not available or just not
suitable. However, DMX control is not suitable for pyrotechnics , large stage
machinery or situations where malfunction may endanger safety- MIDI show
control is generally accepted as safe for these type of applications.
Q: Why is it recommended to use DMX isolators
in a DMX setup?
A: In an Ideal world there's no need to
use isolators for DMX systems, But that being said, there's about four main reasons
why you should use DMX isolation/buffers:
1/MAXIMUM
LOADS: A DMX signal generator
(desk) can only provide enough signal to drive 32 loads (a load is being 1x
DMX device , but some older equipment can use more than this). If you start
trying to add more than this many loads to a DMX branch, it may work most of
the time, until you really need it to work, when it won't, or will become
unpredictable. If more than 32 loads are to be driven , then the setup needs
some sort of signal buffer (signal amplifier).
2/ NO "Y" SPLITS ALLOWED: A DMX run must
always be daisy chained, it isn't possible to make a "Y"
splitter by just joining the cables together. This is because DMX runs at a bit rate
of 250 000 bits per second, the ends of the DMX run "reflect"
signals back down the cable which can confuse receiving devices. These
reflections can be dampened by using a terminating resistor, but when the
DMX run has 2 ends, the signals can just get too confused. Again it's a case
of it might work most of the time , but not when you need it to. Which is
not much good in the middle of a show. A DMX buffer allows a
"branch" to be made from a DMX run without introducing problems.
3/ EARTH
LOOPS: DMX equipment is usually used
spread over a fairly wide area and different sections of DMX devices may be
running off different mains supply points. There is usually a small
difference between the voltage at earth between these points, A small
difference won't usually effect DMX systems, however if this voltage
difference becomes too high, or has electrical noise across it then DMX
devices might start to behave unreliably. If this voltage becomes too great
then it can destroy the DMX receiver and transmitter chips in the connected
equipment.- repairs to expensive lighting desks can get very, well,
expensive. A DMX isolator will stop any earth loop problems from occurring,
because the output DMX , although the same data as the input DMX, does not
have any electrical connection with the input.
4/ CATASTROPHIC
FAULTS: With the wide range of devices that can be
connected to DMX systems , most, if not all of them are powered by mains
power. Dimmer racks connected to 3phase power and most moving lights have
high voltages physically very close to DMX electronics. Dodgy mains
power supply, short
circuits, a splash of water, a dented case, loose PCB's or a loose wire can
mean that 240/415 volts might make it onto the DMX line (normally 5volts) -
A sure way to FRY anything else connected to that DMX branch. - This
could be a safety issue if the control desk becomes live. An opto- isolator
would isolate that branch and stop the damage to the whole DMX
system.
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