Standards for Sensor Coverage – IEC63180:2020 Explained
Many manufacturers make wild claims about the performance of their products without any real evidence to back it up and in the case of claimed coverage performance of PIR (Passive Infrared) motion and presence sensors, it is no different.
Manufacturers may claim that their sensor has a 10mtr coverage or etc, but what is this based on and how was it tested? Here at Smartscape we have seen many cases of sensors not performing and are aware of some manufacturers using very crude methods to come up with the figures they claim.
The New Standard
IEC63180:2020 looks to change this with a completely standardised approach to the testing and displaying of the results, providing accurate data that is consistent and repeatable and able to be used to compare sensors from different manufacturers.
Under the new IEC standard, sensors are tested in their full coverage spectrum in 10 degree sectors (as performance at each point can vary greatly), so for example a 360 degree sensor is tested in 36 positions. For walking motion, sensors are tested for both Tangential (movements across the sensor) and radial (movements towards the sensor). These tests can either be carried out by a temperature controlled robot or by a real human being (datasheets should show what type was used).
If the sensor is also made for presence detection (minor movements, people working at their desks etc) the sensor is also tested for its performance with these types of movements, using a robot arm with both horizontal and vertical movement checks being made.
These tests are run in climate controlled environments to ensure consistent and repeatable results.
Results of these tests are then graphed and detection area can be declared.
Example of tangential motion detection test result, the pink line represents the declared value for coverage.
Some things to note about declared values
Declaring values under the IEC standard allows a manufacturer to have up to 15% of the measured values outside of the declared value. So if a manufacture is claiming for example that there senor has a 20mtr coverage for walking at a tangent to the sensor, there may be points where it gives more coverage than this, but it is also likely that there will be a small amount of points (up to 15%) where it doesn’t quite reach this stated coverage.
Good practise in design
It is good practice when designing the layout of sensors on a project to never design to the extremes of the sensors coverage and if trying to cover large areas with multiple sensors you should overlap the coverage of each sensor by 15-20% to ensure there is no holes and that the space is adequately covered. It is also important that your placement of sensors takes into account the type of space that you are trying to cover e.g. am I trying to to cover a space that is mainly made up of people sitting and working at their desks or is the space going to have a lot of people walking around. Sensors have a very large range of performance based on the type of movement that you are trying to detect, a sensor that is capable of detecting large walking motion at upto 37mtr diameter may only be good for 8mtr diameter when trying to detect small motions like that of people moving while seated at their desks.
Example of a sensors declared values:
For more help on designing a sensor layout for a project or if you have any questions please contact us.
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