DENNARD TYPE 2000 PAN AND TILT HEAD
Whilst the latest high-tech video surveillance cameras get
all the attention, the mounting hardware often remains unnoticed. Thatís not
going to happen with the Dennard Type 200 Pan and Tilt head, one of the biggest
and toughest motorised mounts on the market, capable of shifting loads up to 20
Itís probably fair to say that pan and tilt heads are one of
the less glamorous components in a video surveillance system, yet in many
applications their role is just as important as the cameras bolted to them. The
recent trend has been towards smaller and more sophisticated designs,
reflecting the reduction in size and weight of video cameras. This has
culminated in the development of compact high-speed dome cameras, nevertheless,
there is still a clear need for rugged and reliable pan and tilt heads, capable
of supporting large cameras and their ancillary equipment and able to withstand
the worst that the British weather has to throw at them.
Dennard are synonymous with muscular pan and tilt heads, it
has been making them for more than 35 years, so it should know a thing or two
about them by now. The Type 2000 is their current workhorse model, designed to
meet the needs of such demanding users as the Department of Transport, whoís
cameras end up in some of the most inhospitable locations imaginable. As well
as being tough it is unusually flexible, with numerous variants and options
available, to extend and expand its operational capabilities.
The Type 2000 is a formidable lump, weighing in at 7.5
kilograms, though it can shift almost three times itís own weight, the maximum
all-up load (camera and ancillaries) is an impressive 20 kilograms. The main
unit, with the camera platform in the overhead position measures 255 x 274 x
220mm. From the horizontal the platform can tilt downwards through 90 degrees,
and up through 20 degrees at a speed of 3 degrees per second. Panning speed is
set at 7.5 degrees/sec; models with a pan speed of 11.25 degrees/sec are available
as an option.
The housing is built entirely from pressure diecast alloy
components. Gaskets protect all joints and exposed parts and O-ring seals, to
assure weatherproofing to BS-EN 60529, level IP66. That boils down to no water
ingress whatsoever! Protruding from the base of the unit is a round drilled and
slotted mounting foot; in fact the mechanism will operate in any orientation,
including upright or inverted. The
standard version is fitted with an Ďover the topí camera platform; a side
platform version is also available. The mounting arms are drilled and tapped,
for Dennard IR illuminator fittings.
Standard Type 2000 pan tilt heads are fitted with a single
Amphenol connector, carrying power for the motors; the socket is angled downwards,
to assist weather protection. Incidentally, our review sample was fitted with
AC motors, if required Dennard can also supply variants with DC motors. The
manufacturers can also fit optional feedback potentiometers, (these use a
second connector socket). The pots provide analogue position information for
Dennard controllers that have the facility for programmed patrols or alarm
functions. Still on the subject of options, Dennard have also developed an
autopan module for the Type 2000. Itís a retrofittable slot-in card, that
activates a constant panning motion, so the camera can patrol a designated
area, or give the impression that it is under manual control. The Type 2000 is
designed to operate in a wide range of conditions but it can be kitted out with
a heater and thermostat for extremely low temperature environments, allowing it
to work down to minus 30 degrees centigrade.
Pan and tilt movement is controlled by mechanical limit
stops activating switch arms that protrude through the case. They operate a set
of four micro switches mounted on a single printed circuit board, bolted to the
inside face of one of the side panels. The switch arms are heavily protected
against the weather by rubber seals. The tilt motion limit stops are on the
main side bearing; the striker arms can be set to the required position by
slackening off the four hex bolts that hold the arm onto the shaft. A simple graduated scale moulded into the
arm aids accurate alignment. The pan limits stops are not quite as accessible.
They are located in the cramped space between the mounting foot and the
underside of the casing. Itís not too bad on the ground, for nimble fingered
installers, but it looks like it could be a rather tricky operation, especially
if it has to carried out in situ, up a 30-foot pole on a cold windy dayÖ
The same size anti-vandal hex bolts are used throughout,
including holding the two sides onto the case. Dennard thoughtfully supply an
Allen key in with the accessory pack. Other items include a set of mounting
bolts, a blank Amphenol plug, plastic covers for the end bearings and mounting
blocks for light brackets. The case
sides are held together by just five bolts each side, making it easy to get at
the innards, for inspection or maintenance.
Inside the high standard of construction is immediately
apparent, though our sample appears somehow to have bypassed Dennardís normally
stringent final quality control inspection! A short earth cable, bolted to the
inside of the case and presumably meant to attach to the side panel, was adrift
inside the case. Fortunately it hadnít come into contact with any live
connections but that is hardly the point. It could have, or become tangled in
one of the gear trains, with equally unfortunate consequence. That sort of
oversight is in complete contrast to care taken with the rest of the components
inside the case. The motors and gears are all heavy-duty items, designed for a
long trouble free life with a minimum of maintenance. The wiring is very neat
and kept well out of the way of any moving parts. Modular construction is used
throughout and most of the assemblies can be easily replaced.
The supplied instructions and data sheets are generally well
presented, with photographs and diagrams illustrating important points. The
product guide is multi-lingual, repeated in German and French though overseas
users should be aware that for some unaccountable reason the translations come
and go throughout the book.
Our test unit was a basic Type 2000 configuration with AC
motors and no position feedback control or autopan functions. It was supplied
with a Dennard 1052 control unit, this provides basic pan and tilt switching.
Apart from fitting the camera (and lights) and setting the limit stops, there
are no other controls or adjustments.
Pan and tilt motion is very smooth indeed. The motors and
gears are quiet Ė not quite silent Ė but it never gets above a restrained purr,
even when they are under load. The amount of torque is impressive. We were
unable to come up with a camera weighing anything like 20 kg but we can report
that it moved an equivalent dead weight without any difficulty whatsoever.
There was no sign of strain, or any significant reduction in speed, even when
the centre of gravity was displaced well forward of the main bearing.
The unit came through our brief and somewhat crude
weatherproofing test with flying colours.
It was subjected to a thorough ten minute soaking in a shower, with
regular operating checks. When the test was completed the case was opened, to
check for any signs of water penetration, weíre pleased to report it was as dry
as a bone inside.
Without programmed or proportional control it is difficult
to be too specific about resolution, though momentary activation of the motors -- stabbing at the buttons -- produces
incremental movements of less than one degree.
We do not consider the loose wire inside the case to be
anything more than a momentary (and uncharacteristic) glitch in what appears to
be a tight quality control regime. Documents supplied with our sample included
a long checklist. Itís our guess that the errant wire was probably not replaced
following the visual inspection on the QC docket, which seems somewhat ironic.
The basic design and standard of construction are
outstanding; it looks and feels as though it is built to last the course and
the range of options means it can be configured for a very wide range of
applications. Technically itís not particularly advanced, though thereís
nothing remotely out of date about the materials and components used. However,
in the kinds of environment that the Type 2000 is designed for simplicity is no
bad thing, at the very least it means thereís less to go wrong.
Max load 20kg
Pan speed 7.5-deg/sec
Tilt speed 3-deg/sec
Power supply 230 VAC 50Hz
Dimensions 255 x 274 x 220mm
Product design 9
Build quality 10
General functions 9
Ease of use 10
Manuf. support 10
R. Maybury 1998 0803