GJD350 - D-TECT 50
- CCTV Lens Guide
- Hard Drive Size Guide
Unless selecting a vari-focal camera (with an adjustable lens) It is important to select the correct camera lens option for where the camera is to be positioned. A smaller lens will give you a wider angle but will be "zoomed out more", while a bigger lens will narrow the angle down and "zoom in more". See below to give you some idea on angles of Megapixel HD Cameras:
| Lens in mm | Approx Viewing Angle (degrees) | Ideal Distance (metres) | Typical usage/notes |
|---|---|---|---|
| 2.8 | 106 | <6 | For seeing as much of the immediate area as possible such as above a doorway/low down/garage soffits (edges can appear slightly warped/distorted) - clearly "zoomed out" |
| 3.6/4 | 83-90 | <12 | A great general purpose option giving great coverage still in the corner of a room or higher up on second floor soffits with less distortion - more of a natural "zoom" |
| 6 | 56 | 6-20 | Narrows down the angle and zooms in to look past the immediate area a little to gain more detail - down a driveway for example from higher up |
| 12 | 24 | 20+ | Zooms in significantly more to look at a gate, entrance or adjascent building |
| 16 | 19 | 24+ | As above but more so |
The amount of hard drive space you require is dictated by how many cameras, as well as their resolution and frame rate settings. Finally you can often make your storage space last a lot longer by enabling motion detected recording rather than continuous, especially if there are long periods of no activity.
|
Resolution (Megapixels) |
Days of storage provided by 1TB per camera (continuous - full 25 frames per second) |
Days of storage provided by 1TB per 4 cameras (continuous - full 25 frames per second) |
Days of storage provided by 1TB per 4 cameras (50% motion- 15 frames per second) |
|---|---|---|---|
| 1 | 44 | 11 | 36 |
| 2 | 22 | 5 | 18 |
| 3 | 17 | 4 | 14 |
| 4 | 11 | 3 | 9 |
| 5 | 9 | 2 | 8 |
| 6 | 8 | 2 | 6 |
| 8 (4K) | 5 | 1 | 4 |
| 12 | 4 | 0.5 | 3 |
As a rule of thumb we recommend a minimum of 2 Terabytes per 4 x 2-4MP HD cameras, as this should give you 2 weeks to a month with a few adjustments on motion detected recording. You may only require the full 25 frames per second on certain cameras if things are fast moving.
(All of our hard drives come fitted and are CCTV specific from one of the major brands)
GJD350 - D-TECT 50
The D-TECT 50, BS 8418 compliant movement detectors combine advanced signal processing and unique optical systems, which allow for the beam range to be programmed from 25 to 50 metres, avoiding boundary overspill, making it particularly effective for perimeter detection.
- Detection area of up to 50m
- Adjustable pan and tilt
- A conduit cable adaptor is available
- Engineer friendly features to ease cable termination, set-up and servicing
- Covert sensor module
RANGE: From 25m to 50m programmable
COVERAGE: Detection Area 50m x 10m
ADJUSTMENT: 180º pan + 90º tilt
MOUNTING HEIGHT: Optimum 3m
FRESNEL LENS: 12 zones for each Pyro pair
CUSTOMISED OPTICS: Double silicon shielded quad element eliminates
50,000 Lux of white light
INDICATORS: 1 x Blue LED on detection (configurable on/off)
OUTPUTS:
2 x volt-free, silent solid state magnetically immune, 2
x neg, switched plus one common tamper (front and
rear switched)
POWER INPUT: 9 - 24 AC/DC
CURRENT: 12 mA (12V nominal)
PULSE COUNT: 1-2
WALK TEST: Output test mode with LED indication
OPERATING TEMP: -20ºC to +55ºC conformally coated electronics for
increased stability
TEMP. COMPENSATION: Digital sensitivity adjustment
TIMER OPTIONS: 2 to 60 seconds
LIGHT SENSING: Dusk (2 Lux) to 24 hour
HOUSING: High impact zinc alloy
PROTECTION RATING: IP55
DIMENSIONS 145 x 120 x 115 mm
WEIGHT: 750g NET, 880g GROSS
CABLE <200M: Utilising all five outputs (incl. tamper) - 12 core
7/0.2mm
CABLE <500M: Utilising all five outputs (incl. tamper) - 12 core
16/0.2mm
