Choosing the Best Passive Infrared Sensors
Are all PIRs the same or do the better and more expensive ones really offer superior performance? What sorts of features offer end users and installers the best results?
A: Quality sensors are superior, especially in challenging installations. If you’re looking to protect a space that is not perfect for PIR detection every day of the year, features to look for include sensors with dual edge or quad sensing zones and an array that incorporates look-down zones, as well as more than one sensing range and the greatest possible number of discrete zones. Look for surge and low voltage protection, as well as RFI suppression, pyro electric sensing elements and adjustments that let you alter the range or mask zones.
Walk-test is a valuable feature as are LED-supported latching and a plug-in test meter. Other features to look for include fast-change sensor head, anti-masking (a low-power active infrared transceiver), tantallum capacitor-based RFI and EMI protection, a high signal-to-noise ratio, trouble log capability, auto self-test capability and a temperature range of -10C to +50C. Mirror optics are better than Fresnel lenses – more discerning so the sensor can be more highly tuned without being prone to false alarms.
Better PIRs will have silent alarm relay, multi-facted reflectors, low voltage signal and some enhanced processing or design characteristics that allow sensitivity to be linked to rate and rise of threshold, duration of zone disturbance and intruder presence in both elements. They’ll also have a tamper contact, site-adjustable sensitivity, first-to-alarm memory and temperature compensation. Good wireless sensors will have encypted pathways, not just 433MHz. We also like spread spectrum, 3DES, video verification and ratings like IP66 and IK10.