Room Silent Zone Modules

Silent Zones are used to create areas where the warnings emitted by the Personal and Vehicle Alarm Devices are ignored. Silent Zones are standard on the vehicle for the Operator but can also be installed in locations where personnel are protected by walls and guard rails. Personnel in Offices and Machine Areas will not be distracted by the warning signals as vehicles drive by. Silent Zones can be Oval in shape up to 6.7m in diameter or Linear up to 6.3m in length.

Typical Silent Zone Locations
* Cab of Forklift
* Safe Areas Protected by Guard Rails
* Offices with vehicle paths nearby
* Personnel Work Areas

Silent Zone Module Description

The Silent Zone Module is a rectangular-shaped box (25cm. x15.8cm x 8.8cm) that can be placed on a desk, table, or file cabinet inside the office area. (see Figure above right). It plugs into a 120 VAC power source. A rocker-type power switch, located at the rear of the case, turns the unit ON and OFF. (see Figure below right) A blue LED in the front of the case illuminates when the unit is ON.

Silent Zone Size Adjustment

The field size of the Silent Zone Module is adjustable and may require adjustment by the user to match the field size to the dimensions of the room. As shown in Figure 2, the silent zone field is elliptical in shape and its size should cover areas in the office where PADs may be routinely worn. The major axis (i.e., large dimension) of the elliptical silent zone field is in a direction parallel to the front face of the module (i.e., face with the blue LED). Since silent zone fields will penetrate most walls, the field size should not be too large so as to extend outside the office into areas that are exposed to lift truck traffic. Silent zone fields that are too large may extend out into danger areas and prevent pedestrians from getting needed alerts. Figure 3 depicts an example of a silent zone field that is too large.

Silent zone magnetic field sizes can vary according to what the Silent Zone Module is placed on. Particularly, metal cabinets can affect the magnetic fields and reduce the field size. In general, the size of the major axis of the magnetic field can be adjusted to sizes between approximately 3 and 8 meters. Sizes of the minor axis of the field is approximately 80 % of the major axis.

Checking/setting the silent zone field size can be accomplished by positioning a lift truck at the nearest point outside the office and using a PAD to map the field. The PAD will be silent as long as it is in the silent zone field and will sound alerts when it is outside the silent zone field.