Increasingly, external space detection devices are deployed to act as triggers for other systems. Whether used for lighting, surveillance, building automation or traditional intruder detection, today’s sensors must offer flexibility, stability and accuracy.
When it comes to external detection systems, external space detection is still a peripheral option for many. Typically, the sensor of choice in such applications is active infrared beam sensors. Many still feel that space detection devices – usually PIRs or PIR and microwave combinations – are vulnerable to nuisance activations in more unstable environments.
The general perception that outdoor detection devices are susceptible to false alarms is somewhat outdated. Credible manufacturers have enhanced product design over the years, and external detectors can often be more stable than average internal sensors!
Too often the focus for external detection devices falls onto stability … and stays there! In external applications, there often aren’t any false alarms, but instead there are nuisance alarms. Something will trigger the detector; it’s just not what the user thought it might be!
In truth, the issue of catch performance is far more important than stability. Nuisance alarms will happen in an external environment, and when designing a system this has to be considered. However, missing a genuine event is more critical, because the point of external detection is to identify threats, usually intruders, before they have an opportunity to cause loss or damage.
A trigger source
The SIP-3020/5 from Optex is a part of the company’s Redwall range. It is an external PIR detector with a range of 30 x 20 metres, and is designed for use as a trigger; it can be deployed in video surveillance applications and for other site management tasks. Mounting height is between 2.4 and 4.0 metres. The unit also includes a discrete PIR on its base for creep protection.
Other features include automatic sensitivity adjustment based on light and temperature, anti-vandalism features and intelligent adaptive signal processing.
The detector is provided with a masking kit, and there are also some optional parts for product adjustment, such as a visual alignment tool and walk tester.
The installation of the detector is simple. Wiring connections are made via the cable-managed bracket and are straightforward. Removing the cover plate reveals 4 DIP switches, 3 sensitivity adjustment switches and a connection for the walk test unit. Alignment uses the visual tool and a detection area plate, and this is then verified using the walk test tool.
Once aligned the configurations can be finalised. These include setting the sensitivity for the far area, near area and creep zone. The DIP switches are used to set AND/OR, detection range (this effectively deactivates the far detection zone if the range needs to be reduced) and alarm interval time.
Once aligned and configured, the detector will operate consistently. The Redwall range has been around for a long time, and is proven in the field. New developments build upon the established and stable detection technologies for which the Redwall devices are well known.
Stability has been tested in the past by Benchmark, and the Redwall range always delivers in terms of performance. The SIP-3020 is consistent, detecting all genuine intrusion attempts and all potential sabotage attempts. Catch performance is very good, and delivers accurate and timely detection.