Response time
The response time of the sensor is, relatively speaking, the “speed of reaction” to the monitored event. Indicated by the time that elapses between the event being recorded and sending a signal to the control panel and/or turning on its own siren.
Theoretically, the shorter the response time of the sensor, the higher the overall reliability of the system, the faster it is able to respond to an event. At the same time, it is worth noting that in most models this time is measured in hundredths of a second — on average, from 0.03 to 0.15 s. Such a difference is fundamental only in very specific situations, when the count really goes to fractions of a second — for example, if a sensor is used to stop an industrial mechanism when a person appears in a dangerous area. In simpler cases, this parameter can be ignored.
Working hours
Operating time of the self-powered sensor on one set of batteries or battery charge (see "Power"). Note that this indicator is quite approximate — it is usually indicated either for an perfect or for a certain “average” mode of operation. The real battery life also depends on a number of practical nuances: the frequency of operations, the communication range, the level of interference, etc., up to the air temperature. So in fact, the operating time may differ from the claimed one, and in the other direction. Nevertheless, according to this characteristic, it is quite possible to both evaluate the overall battery life of the sensor and compare different models with each other: the difference in the indicated operating time usually fully corresponds to the difference in real battery life.
Note that modern sensors have very low power consumption, so their operating time is calculated in months.
Protection class
The class of protection against adverse environmental conditions, which corresponds to the sensor body.
This parameter is traditionally designated according to the IP standard - marking "IP" with two digits, each of which corresponds to its own indicator. So, the first digit describes the protection against the ingress of dust and foreign objects; among the sensors for this indicator, there are such options:
— 2. Protection against objects with a thickness of 12.5 mm or more; prevents penetration of fingers.
- 3. Protection against objects with a thickness of 2.5 mm, in particular many tools.
— 4. Protection against objects with a thickness of 1 mm, such as most wires.
— 5. Complete protection against contact of the “filling” with foreign objects, resistance to dust (dust can penetrate inside the case, but in small quantities that do not affect the operation of the device).
— 6. Completely closed case, excluding the ingress of dust.
Note that this parameter describes only the mechanical protection provided by the case (roughly speaking, the size of the holes in it and objects that can penetrate through them). In this case, there is no question of protection against opening and interference with the operation of the sensor - this is a completely separate nuance implemented in other ways (for example, by installing a case opening sensor).
The second digit characterizing the protection against moisture can b...e as follows:
- 0. The complete absence of any protection, water ingress to the body is not allowed. As a rule, means that the sensor is intended exclusively for internal use.
— 1. Protection against vertical drops of water.
— 2. Protection against vertical drops when the body is tilted up to 15° from the standard position.
— 3. Protection against splashes falling on the body at an angle of up to 60 ° to the horizontal. The minimum indicator that allows you to talk about resistance to rain.
— 4. Protection against splashes from any direction. Allows you to safely endure rain with strong winds.
— 5. Protection against water jets from any direction, resistance to storms.
— 6. Protection against strong water jets or strong sea waves (when the device can completely hide under the wave for a short time).
Higher levels of moisture resistance, allowing immersion in water, are not found in modern sensors - this is simply not required, for the most severe conditions, a level of 6 or even 5 is usually sufficient.
The degree of protection according to IP is especially important to consider when choosing outdoor sensors (see "Use") - they are the most susceptible to adverse effects. It is worth noting here that if the degree of protection is not specified, this does not mean that the device is not protected. It's just that it has not passed official IP certification, but the actual degree of protection can be quite high (in such cases it should be clarified according to the manufacturer's documentation). At the same time, we emphasize that a certain degree of IP protection in itself does not guarantee the possibility of outdoor use - after all, the sensor must withstand not only moisture and dust, but also temperature extremes, sunlight and other adverse factors.
Operating temperature
Ambient temperature range in which the sensor is guaranteed to remain operational.
All modern sensors are able to transfer the temperatures typical for residential and office premises without consequences. Therefore, it makes sense to pay attention to this parameter mainly in those cases when the sensor is planned to be used in more unfavorable conditions — for example, on the street, in an unheated room, in a “hot” industrial workshop, etc. At the same time, we emphasize that even for the most "Heat-resistant" models are undesirable exposure to direct sunlight — they can heat the case to temperatures that are much higher than permissible.
Maximum humidity
The highest relative air humidity at which the sensor can be used.
Many models can easily tolerate short-term (up to several hours) stay in a more humid atmosphere; however, for a complete guarantee, it is still better not to exceed the permissible humidity. As for specific numbers, in residential/office spaces (and similar environments) the relative humidity rarely exceeds 70%. But for outdoor use and rooms with high humidity (swimming pools, laundries, etc.), it is advisable to use sensors designed for a humidity of at least 90%.
