What Are PIR Sensors?

PIR (Polyisocyanurate Foam)

PIR

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PIR (Polyisocyanurate Foam)

Full name Polyisocyanurate Foam, Chinese name "Polyisocyanurate", also known as "Polyisocyanurate", also known as "Polyisocyanurate PIR" or "Tripolyester PIR" . PIR is made of foamed material that reacts with polyether after being reacted with isocyanate by catalyst. Its physical and fire resistance are more excellent than general polyurethane. It is an ideal organic low-temperature thermal insulation material with small thermal conductivity, light weight, shock resistance, and strong adaptability. It is widely used in thermal insulation of oil refineries, chemical plants, ethylene, fertilizers, cold storage and construction industry.

Chinese name

Polyisocyanurate

Foreign name

Polyisocyanurate Foam

Also known as

Polyisocyanurate foam

Operating temperature range

-196 ° C + 130 ° C

Chinese translation: polyisocyanurate foam

1.Excellent thermal insulation performance, the first of all cold insulation materials;

2. The fire performance complies with GB8624 flame-resistant B1 grade and American ASTM E 84 standard;

3. It has excellent properties such as strong compression resistance, low thermal conductivity, and excellent dimensional stability when used in ultra-low temperature environments;

4. Cutting and forming can meet the design requirements of composite multi-layer mechanisms of various thicknesses to ensure construction quality;

5. The operating temperature range is up to -196 ° C + 130 ° C

PIR is a database that integrates public resources for protein function prediction data, and its purpose is to support genomic / proteome research. PIR works with other organizations to form the PIR-International Protein Sequence Database (PSD), a major database of predicted proteins, including 250,000 proteins. PIR performance

PIR is a new type of organic polymer thermal insulation material. It is mainly composed of isocyanate and polyether (Ployol), plus catalyst, fire retardant and environmental protection foaming agent. The foamed polymer produced by mixing, reacting, and foaming under the process conditions is fully mixed. Because this foam polymer has independent sealing

The appearance of PIR (Protein Information resource, protein database) preceded the nucleic acid database. Around 1960, Dayhoff and his colleagues collected all known amino acid sequences at that time and compiled the Atlas of Protein Sequences and Structures. From the data in this atlas, it evolved into a subsequent protein information resource database.

In order to improve the mutual agreement between protein prediction and experimental data, PIR has established a system that allows researchers to submit, classify, and extract literature information. PIR provides

Regular bioinformatics tools are also available on the PIR site for data mining.

PIR: Passive infrared detectors

In the security field, PIR is the abbreviation of Passive Infrared, that is, passive infrared technology. The full name of PIR detector is Passive Infrared Detector, that is, passive infrared detector or body sensor, sometimes called Passive Infrared Sensor, and detectors in security industry are mostly called Detector.

PIR installation

As the passive infrared detector belongs to a kind of weak signal detection equipment, attention must be paid to some details such as height and sensitivity during installation. To properly install a passive infrared detector, you must have the following information: first, you must understand the performance characteristics of the detector, second, you must reasonably determine the installation location, and finally you must carefully debug. It cannot be said that the detector can report that it has been installed. So how to determine the installation position of a passive infrared detector?

Determine the normal installation angle according to the instructions: the installation height is not arbitrary, it will affect the sensitivity of the detector and the effect of preventing pets. Imagine that if a detector is installed at a height of 2M and a height of 2.5, then when a moving object moves from the ground, the frequency of cutting the bright and dark areas is different. Should not face glass doors and windows: Passive infrared detectors face glass doors and windows, there will be two problems: First, white light interference, although PIR has a strong suppression of white light, but it is not 100% suppression after all. Therefore, avoid facing the glass doors and windows to avoid the interference of strong light. The second is to avoid complicated environmental interference outside the doors and windows, such as crowd movement, vehicles, and so on. It should not be directly facing the hot and cold vents or hot and cold sources: the sensing effect of the passive infrared detector is closely related to the change in temperature. Both the hot and cold vents and cold and hot sources may cause false alarms by the detector. Detectors and sometimes air convection through doors and windows can also cause false alarms. It is not advisable to face the object that is easy to swing: the object that is easy to swing will make the microwave detector work, so it may also cause false alarms. Note that the purpose of installing detectors on illegal invasion routes is to prevent illegal intrusion by criminals. Before determining the installation location, the main entrances and exits of the building must be considered. In fact, we prevented entrances and exits, and intercepted illegal intrusion lines, and thus achieved our goal. Reasonable selection: Passive infrared detectors have a variety of models. For example, DFM-235R, DT-55R, DT-7380R, etc. produced by Mei'an Technology, from single infrared to three technologies, from wall-mounted to ceiling-mounted, then the detectors to be installed must consider the prevention of space Size, surrounding environment, characteristics of the entrance and exit, etc. Sometimes it is necessary to consider replacing Fresnel lenses to meet the requirements.

PIR debugging

After the detector is installed, commissioning the detector is the last thing to do. There are two methods for the debugging of the passive infrared detector. One is walk test, that is, the debugger walks the s-shaped line in the warning area to sense the length of the warning range and so on. This can be understood from the figure.

The microwave sensitivity and the infrared sensitivity should be adjusted separately through the step test method. Too high or too low sensitivity will affect the prevention effect. Sometimes due to seasonal changes, sensitivity is adjusted separately in winter and summer. The microwave sensitivity must not be too large, because the microwave is only penetrating. Pay attention to it when debugging.

The second method is meter measurement. Some detectors have a background noise voltage output interface. Use the voltage of a multimeter to test. When the detector is on alert, the output voltage of its static background noise indicates the interference of the interference source. To determine whether this type of detector is suitable for this location.

The above part is just the author's analysis of the basic commonality of the use and installation of passive infrared detectors. Various brands have their own unique methods in infrared processing. Therefore, we must read the instructions carefully before using the installation. The most important thing is that Through the accumulation of actual work experience, the characteristics of the detector must be better understood, so that the role of passive infrared detectors in security engineering can be better played. ^[1]