A basic Lone Worker alarm system would consist of a receiver / alarm panel and a lone worker transmitter. With a typical range of 3Km, the transmitter will usually enable an alarm to be raised anywhere within 25 square Km.

The lone worker transmitter is worn by the operative and is equipped with both motion sensing and a personal attack button as means of raising an alarm signal.

When the PA button is used to raise the alarm, the alarm signal is sent immediately to the panel and indication is given as to which transmitter sent the alarm. The Lone Worker transmitter is also latched into an alarm condition on activation, and will activate its on board sounder to assist with location and alert anybody in the near vicinity. The transmitter will also continue to send out radio alarm signal and if the panel is reset without attending to the Lone Worker the panel will be repeatedly re-triggered.

To prevent accidental abortion of the panic signal, once in an alarm condition a Lone worker transmitter can only be reset by pressing both the reset buttons simultaneously on the transmitter.

If the motion sensor fails to detect any movement from the user for a pre-set period of time, for example 90 seconds, the unit will emit a loud pre warning sound for a short period, eg.15 seconds, during which time, the transmitter may be reset by either tapping the unit sharply, or pressing the pause button. If the unit is not reset during the pre warning period a distress signal will be sent to the receiver panel as if the PA button had been pressed.

When an alarm signal is received at the panel it will be displayed on the panel with audible indication and it can be used to drive sounders, Scada systems, telephone devices, radio paging, relay outputs etc.

Systems may be single or multi channel and the receivers may be fixed, portable, or vehicle mounted. They can be integrated with GPS systems and existing radio platforms to provide communications and location where the usual methods of communication are impractical.

t should be remembered that a Lone worker alarm system, no matter how effective it may be, is only part of the solution. A good solid set of procedures should be introduced concerning the use of the system to ensure it is used properly, tested regularly and the staff know what to do in the event of an alarm condition. A log similar to that used to record fire alarm tests, incidents and maintenance works on the system could well prove useful in keeping track of any problems.

Different situations demand different features and settings. Senflow's systems are designed to be versatile and flexible and as a result most of the features are programmable no cost options.