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If there's one thing most security installation engineers dread it's messing around with a dead camera on the top of a twenty-foot pole or some even more treacherous location. Add in the British weather and the security industry's version of Sod's Law (there will probably be nothing wrong with the camera and the fault will always be in the last place checked…), and you have a very convincing argument for a product like the Pelco ES31C, a rugged and fully integrated motorised camera system from a company with an impeccable pedigree and track record for dependability.


The keyword here is 'integrated' which rightly suggests that the camera, its motorised mount hardware and associated systems are all designed from the ground up to work together. This has major implications for ease of installation, configuration and long-term reliability. That's not meant to imply that motorised camera systems assembled from components made by different manufacturers are inherently less reliable but there is a good chance installation times will be longer and control systems will necessarily be more complex, or less flexible, or both.


The EC31C is a member of Pelco's Esprit family of products, it is rather grandly described as a 'Positioning System with IOP' (Integrated Optics Package), otherwise known as a pan/tilt head with built in camera and lens… The particular model we have been looking at is the ES31CBW18, which is the top of the range version with a high resolution colour camera featuring an 18x optical zoom and 4x electronic zoom plus a built in window wiper; models with black and white cameras, a range of zoom options and with and without wipers are also available.


Starting with the camera section specs, our sample has a F1.4 lens with a 4.1 - 73.8mm focal length. Low light sensitivity is quoted as 0.2 lux (slow shutter mode), the 0.25-inch interline CCD, has a 752 x 582 pixel array giving a claimed resolution of around 460 lines. Focus, exposure shutter speed and white balance are fully automatic (with manual overrides). The camera is remotely configurable via a menu-driven on-screen display system, the main options are auto focus on/off, auto iris (auto/manual, iris level & peak level), switchable IR filter and level, backlight compensation with adjustable sensitivity area and variable gain/AGC. Picture sharpness and shutter speed can also be manually adjusted.  The on-screen displays also cover programming the motorised head functions and positioning and we'll look at that in more detail in a moment. To round off, the front window has a built-in heater/demister and the whole caboodle is powered by an external 24 volt AC supply (120/230 volt models are also available).


The imposing and very sleek looking pan/tilt assembly has an equally impressive specification, pan speed is variable, between 0.1 and 40 degrees per second variable speed and 100 deg/sec in 'turbo' mode, with proportional pan and 360 degrees rotation. Vertical tilt is from –90 to + 40 degrees at 0.1 to 20 deg/sec variable speed. Preset pan/tilt speeds are 100 and 30 deg/sec respectively. General operating parameters are a safe temperature range of -45 to 50 degrees centigrade (60 degree C tolerable for short periods) and it will remain operational in wind speeds up to 90 mph and withstand up to 130mph, though whether or not whatever it is bolted to will stay upright in such conditions is open to debate...


Camera set-up and the motorised mount functions can be controlled and programmed using a wide range of Pelco system components (video switcher/controllers CM6700/8500/9500 & 9760 and keyboard units KBD200/3000 & 300V), for the record our review sample was used with a CM6700 matrix camera switcher and KBD300 Universal keyboard. The EC31 can communicate with its control hardware using either RS-422/RS-485 protocols, or Pelco's proprietary Coaxitron system, which uses the video connection to carry telemetry and data to and from the camera; note that some setup and control functions may not be accessible using some combinations of components. 


The standard of construction is high. The camera housing is made from heavy gauge die cast and sheet alloy materials, the finish is very good indeed and it is clear that a lot of attention has been paid to weatherproofing. Access to the camera's innards is via a hinged, spring-loaded panel on the top (complete with padlock fittings). Once open the all-in one camera module or 'sled' can be easily lifted out with just one hand (worth knowing when you're perched on top of a ladder thirty feet above the ground). The pan/tilt mechanism is superbly well engineered and looks as though it'll withstand just about anything the British climate (and vandals with good aim…) can throw at it. It has two gearless drive trains, using toothed nylon belts, which undoubtedly contributes to its smoothness, quietness of operation and impressive turn of speed. Camera and motor controls and the communications electronics are all mounted on a single PCB housed in one of the two side lobes, access to either side of the unit is via a single captive screw. Re-fitting the covers and aligning the seals can be quite tricky though, so it's a good idea to carry out any adjustments on the ground (there's a pair of DIP switches for setting communications protocols).



Installation is unlikely to pose too many problems for experienced engineers, and like the rest of the unit the mounting hardware is very well engineered, functional and easy to use. The same goes for the instructions, which appears to have been written by someone who actually knows what they are talking about. The unit connects to the outside word using a single, small multi-way plug on the end of a flying lead emerging from the base of the pedestal; this mates with a socket mounted in the top of the transformer module, which once again contributes to easy installation and maintenance.


The remainder of the on-screen menus, mentioned earlier, are mostly concerned with programming the unit's motion and movements. The options include setting limit stops, tour pattern length (1.5, 3 or 6 minutes, or two half-patterns lasting 45 seconds, 1.5 or 3 minutes), action on power up (default configuration, park on preset 1, auto scan, random scan, full pattern, and half pattern 1 or 2). Panning motion can be set to normal or proportional, which basically means the pan speed slows down at higher zoom settings. Limits can be set on scanning speed (1 to 40 deg/sec) and there's an option to reset the unit to its factory defaults. A feature called speed profile allows the operator to adjust the unit's behaviour in wind speeds of 50 or 90mph (sets limit on pan/tilt speeds at higher wind speeds), and there is a set of wiper adjustments  (momentary wipe, variable dwell time and wipe duration).



Image quality is very good indeed and our sample performed at or close to the manufacturers specifications. Resolution was within a whisker of the stated figure and colour accuracy remained stable under mixed lighting and sudden changes in scene lighting. In low light conditions the camera automatically switches to black and white mode and it continues to produce a useable image in quite difficult conditions. The electronic zoom takes over seamlessly when the optical zoom reaches the end of its travel; there is a tiny increase in noise levels but in good light it is barely noticeable. The only minor quibble concerns the speed at which the camera returns to colour when light levels increase, it can be very slow and occasionally it is necessary to 'nudge' it by pointing it at a brightly lit area. Noise levels in all operating modes are well below average and only become significant at the limits of the cameras operating range. The auto focus, exposure and white balance systems proved to be very agile, requiring a minimum of manual intervention.


The pan/tilt mechanism operates flawlessly; it's fast and highly responsive to the joystick control  – turbo mode is most impressive -- yet it is able to move in minute increments. The motion is smooth and controlled with out the slightest suggestion of lag or overshoot, though it does put on an unexpected turn of speed when it shifts up a gear into turbo mode, at around the halfway point on the joystick's travel.



There's every indication the ES31C will provide long and faithful service. Everything about it says quality and attention to detail, from the obvious effort that has been taken to weatherproof the unit, to the over-engineered wiper mechanism. Mechanical construction is matched by the video performance, which ensures the camera will produce a detailed, well-balanced image more or less autonomously under the widest possible range of illumination levels.




Design and design features                      *****

Circuitry and components                *****

Ease of installation and wiring            ****

Range and variety of functions            *****

Accompanying instructions              ****                          

Technical advice and backup            ??    

Value for money                         ??                          



ã R. Maybury 2001 2203



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