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Safety LiDAR

What is a safety sensor?

A sensor that is designed in accordance with international standards and is certified by a third-party certification body is called a "safety sensor".


Among the safety sensors, the certified LiDAR is called "safety laser scanner".

In Hokuyo line-up, safety laser scanner is UAM-05LP-T301/T301C.

International standards required for safety LiDAR

In order to be certified as a safety laser scanner, it is required to meet the following international standards.


・ ISO 13849 (JIS B9705) PLd category 3
・ IEC 61508 (JIS C 0508) SIL2
・ IEC 61496 (JIS B 9704) Type3


* Standards differ when certified as a safety sensor in categories other than laser scanners.

IEC 61496 (JIS B9704)

□ "Safety of machinery-Electrical detection and protection equipment" Requirements for sensor design and testing


It is a standard applied to devices (ESPE) that electrically detect the human body and output control signals to protect it, such as safety laser scanners.


It stipulates failure detection performance, software design policy, temperature resistance performance, EMC performance, vibration resistance / impact resistance, indicator lamp color, label description content, instruction manual description content, etc.


Electrical detection and protection equipment: ESPE (Electro-Sensitive Protective Equipment) is classified into four types, and the required items are different for each type.


IEC61496-2 (Type2,4): Detects the human body by blocking the laser formed between the light emitting part and the light receiving part
IEC61496-3 (Type3): Detects the human body by reflecting the laser light
IEC61496-4 (Type4): Detects the human body using image sensing technology


  Type
1 2 3 4
Safety performance according to
IEC 62061and/or ISO 13849-1
N/A SIL 1 and SILCL
1and/orPL c
SIL 2 and SILCL
2and/orPL d
SIL 3 and SILCL
3and/orPL e
UAM-05LP-T301 / 301C is classified as Type 3 because it is a reflective sensor.

ISO13849 (JIS B9705)

□ "Safety of machinery-Control system safety-related department" stipulates the ability to perform the safety functions of the control system


Performance level (PL) defines the capabilities of safety-related departments and is evaluated on a scale of 5 from a to e.
UAM-05LP-T301 / T301C is classified as PLd.
The system must be configured with PL components that are PLr or higher as determined by risk assessment.

IEC 61508 (JIS C 0508)

□ "Functional safety of electrical / electronic / programmable electronic safety-related systems" Requirements for reliability and development process


Functional safety specifications for UAM-05LP-T301/T301C

Functional safety SIL 2 (Type B、HFT=1)(IEC61508)
PFHd 7.8×10-8 (T1=20 years): when the master-slave function is disabled
1.6×10-7 (T1=20 years): when the master-slave function is enabled


SIL: Safety Integrity Level (SIL), which is defined in four stages from SIL1 to SIL4. It can be obtained from PFHd, which is the sum of the failure rates of the parts that make up the sensor.


HFT: Abbreviation for Hardware Fault Tolerance.
It indicates that failure of the subsystem with "number + 1" may cause a loss of function.


PFHd: It indicates the probability that the sensor will fail dangerously in one hour.


SIL PFHd
1 10-6 or more and less than 10-5
2 10-7 or more and less than 10-6
3 10-8 or more and less than 10-7
4 10-9 or more and less than 10-8

TYPE: IEC61508 classifies the equipment that constitutes a safety instrumented system into TYPE A and TYPE B.
Simple devices such as valves, relays and switches are TYPE A, Complex devices such as smart transmitters and PLCs are classified as TYPE B. UAM-05LP-T301/T301C is classified as TYPE B.


T1 = 20 years: Safety function confirmation interval. Used in PFHd calculations.

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