ParScan
(?1986)The ParScan is a lightweight, compact 1kW spotlight with remote control of movement and an integral colour change system where up to sixteen colours may be included in a continuous strip within a scroll mechanism.
The combination of a Par 64 1kW source, a comprehensive colour change unit and automated movement provides an intense beam of coloured light which can move at a variable speed. This finds applications not only for special effects, but also in situations where spotlights are in inaccessible positions, or where weight restrictions imposed by unsupported trussing limit the number of spotlights capable of covering the stage.
ParScan is supplied complete with a barrel clamp, and instructions on making a colour scroll. Alternatively, a ready-made scroll may be purchased as an accessory.
Specification
Par
64 Light Source
Beam spread is determined by the choice of 1000W Par 64 sealed-beam
tungsten halogen lamps. These lamps are available with a clear,
stipplied or spread lens front all producing an oval beam distribution.
The lamp may be rotated in its housing to locate the optimum
position for the oval beam at any attitude of the spotlight.
Colour
Unit
The integral colour change mechanism utilises any selection of
between three and sixteen colours which are formed into a continuous
strip and attached to twin rollers which spread the colour across
the front of the spotlight. The rollers are independantly driven
by two electronically-controlled servo motors via toothed-belt
drives. The use of belt-drives enables the scrolls to be easily
rotated manually when the colour strip has to be replaced, and
also, it reduces the overall width of the luminaire.
The on-board microprocessor maintains an accurate count of not
only the number of roller revolutions required for each colour
position, but also the number of interruptions in a beam of light
caused by opaque tapes placed on each frame of colour, and recorded
by the optical sensor. This dual counting system ensures reliable
and accurate positioning of the chosen colour filter within the
beam of light.
In addition to selecting the choice of colour, the control system
may also instruct the ParScan to change colour at a given speed.
Colours may be selected from within 2.5 seconds to a maximum
of 20 seconds if a slow change of colour wash is required.
Colour
Scrolls
The strip of filters which form a scroll may be made to suit
individual needs or purchased as a ready-made accessory in one
of a choice of specially recommended colour selections. Each
ParScan is supplied with full instructions on how to produce
a scroll, and rolls of the self-adhesive and opaque tape are
available as an accessory to make custom scrolls.
The strip of colour filters is easily attached to the mechanism
by twisting three quick-release fasteners on the front of the
unit, hinging the front panel to gain access to the twin scrolls,
and then attaching each end of the strip to the scrolls by a
piece of self-adhesive tape. The length of filter material is
then rolled onto the scrolls manually, and when tight, the edge
of the strip is looped into the optical sensor unit. With the
hinged panel relocated, power may then be applied to the system,
whereupon the ParScan follows a preprogrammed self-checking cycle
during which the number and length of each colour frame is calculated
and stored for future reference.
Two standard scrolls are available as accessories: a selection
of ten general tints for theatrical use, and ten stronger colours
for special effects purposes. All colours are taken from the
Strand filter range, and each scroll comprises the following
selection:
| Drama | Effects |
Clear |
Clear |
Movement
Two high-torque servo motors provide a range of movement of up
to 340deg horizontal pan, and up to 220deg vertical tilt. The
low-voltage motors are belt driven to provide positional resolution
and a repeatability of one degree in either axis.
The advanced software controlling the movement of the ParScan incorporates acceleration curves to minimise any shock on the filament even during repeated fast actions.
Each ParScan may be instructed from the control desk to move at a preset speed, so although a complex movement can be programmed to coincide with a cue, the individual ParScans can follow their own course in any time from an almost instantaneous two seconds, to a leisurely twenty seconds.
Microprocessor
Control
All of the automated functions of the ParScan are controlled
by a central microprocessor unit housed in the stirrup assembly.
This micro-computer decodes information from the data signal
to control the pan and tilt movements, colour selection and speed
of action.
When power is applied to the system, each ParScan unit is programmed to perform a complete range of movement and if there is any obstruction, the microprocessor records the reduction in range and compensates accordingly.
Multiplexed
Control Data
A single multicore cable supplies each ParScan with power and
multiplexed colour and movement instructions via a rugged, latching
multipin connector.
Ninety-nine ParScan units may be individually addressed and controlled,
and the system may be extended by selecting two or more units
to the same channel number. Channel numbers are set by selecting
the address on the two-digit thumbwheel switch found on the inside
of the stirrup assembly. A separate Showchangers data sheet describes
the options available for the connection and installation of
a ParScan system, and includes details of more extensive systems
which include other units from the Showchangers range.
Power
Supply
Power at mains voltage, and 24V d.c. is supplied by the single
multicore cable connecting each ParScan to the control system.
The colour change unit is securely bonded to the housing of the
luminaire, and both parts of the assembly are separately earthed.
Two versions of ParScan are available for either 110V or 220/240V
applications.
Fan
Cooled
ParScans are equipped with low-noise fans which direct an airflow
through the electronic circuits, and also onto the colour compartment
thus extending the life of the filter strip.
