Care in choosing a suitably rugged PC, be it a Notebook, Tablet or Chassis is crucial where it is envisaged the system is to be used outside the relatively benign environment of the office. A set of ratings have been produced to fix some definable standards so that a judgement can be made as to the suitability of a particular computer system to a task and are most commonly are defined in two forms:-
The military standard MIL 810E and F (F superseded E in January 2000) is a complex testing protocols for rain, humidity, salt fog, sand/dust, vibration, shock and temperature, among others.(For just how complex you can read the protocols at; www.dtc.army.mil/pdf/810.pdf). This complexity does make it difficult to place in a nutshell all the various aspects of this stringent standard, rather it is best to concentrate on the its most relevant application to portable rugged PC's; that is drop tests and vibration. The MIL-STD 810E/F specification for mechanical shock, for instance, calls for notebook computers to withstand 26 drops, (one drop on each face/edge/corner with display screen closed, and unit powered off), onto 2" plywood over solid concrete without failure from a height of metre. Any computer successfully completing such a test is certified as MIL-STD 810E/F compliant.
In the real world this set of circumstances will be unlikely to be repeated, but it does give a good indicator as to the suitability and likelihood of survival, after all many off-the shelf high street computer systems can barely survive the general knocks in the office, let alone any kind of drop. Possessing a PC system with a MIL specification also means that physically the system will have a longer life, (note the standard 3 year warranty on our Rugged Tablet [RNOTE-TAB] for example), helped by a high resilience to vibration from machinery or vehicle.
IP rating describes the ability of an electrical enclosure to withstand penetration from solids and liquids, in real life most commonly dust and rain water. With electronic equipment choosing a suitable IP level is a critical factor. Below is a table that defines the levels.
| Num. | PROTECTION FROM SOLIDS | PROTECTION FROM LIQUIDS |
|---|---|---|
| 0 | No protection | No protection |
| 1 | Protection from objects greater than 50mm in diameter. (e.g. the hand) | Vertically dripping water and external condensation |
| 2 | Protection from objects >12.5mm in diameter (e.g. fingers) | Dripping water to an angle of 15 degrees from the vertical |
| 3 | Protection from objects with a diameter > 2.5mm ( e.g. tools and wires) | Water splash and low pressure spray up to 60 degrees,limited liquid access allowed but not as to affect operation. |
| 4 | Protection from entry by solid objects with a diameter > 1.0mm | Water splash and low pressure spray all angles, limited liquid access allowed but not as to affect operation. |
| 5 | Protection from dust, though limited ingress is allowed as long as volume does not affect operation. | Low pressure water jets all directions |
| 6 | Complete protection from all solid particulates | Protection from powerful jets of water (e.g. as found on the deck of a ship) |
| 7 | Not applicable | Temporary complete immersion at 0.15 to 1 metre |
| 8 | Not applicable | Permanent immersion. Depth to be pre-defined on a per case basis |
If the PC system is to be used where there is any risk of liquid or dust contamination then choosing a system with a rating of at least IP54 is advisable. Such a rating will allow its use outdoors in the field environment, repelling rain water and wind borne dust to a high degree. However where it is envisaged the system is to be used for several hours in heavy blowing rain or on the exterior deck of a ship a higher IP67 level should be considered. If so contact us for further advice.
E&OE
DataQuest Solutions Ltd 2005