Safety of machinery —
Electro sensitive protective equipment —
Part 3: Particular requirements for
Active Opto-electronic Protective Devices responsive to Diffuse
Reflection (AOPDDR)
Replacement:
This part of IEC 61496 specifies additional requirements for the design, construction and
testing of non-contact electro-sensitive protective equipment (ESPE) designed specifically to
detect persons as part of a safety related system, employing active opto-electronic protective
devices responsive to diffuse reflection (AOPDDRs) for the sensing function. Special attention
is directed to requirements which ensure that an appropriate safety-related performance is
achieved. An ESPE may include optional safety-related functions, the requirements for which
are given both in Annex A of this part and in Annex A of IEC 61496-1.
This part does not specify the dimensions or configurations of the detection zone and its
disposition in relation to hazardous parts for any particular application, nor what constitutes a
hazardous state of any machine. It is restricted to the functioning of the ESPE and how it
interfaces with the machine.
AOPDDRs are devices that have a detection zone specified in two dimensions wherein
radiation in the near infrared range is emitted by a transmitter element(s). When the emitted
radiation impinges on an object (for example, a person or part of a person), a portion of the
emitted radiation is reflected to a receiving element(s) by diffuse reflection whereby the
presence of the object can be detected.
NOTE 1 Under certain circumstances, limitations of the sensor in relation to its use need to be considered. For
example:
– Objects that generate mirror-like (specular) reflections may not be detected if the diffuse reflectance value is
less than that specified for the "black" test piece.
– The determination of the minimal reflection factors for the detection of obstacles is based on the clothing of a
person. Objects having a reflectivity lower than that considered in this part may not be detected.
Excluded from this part are AOPDDRs employing radiation of wavelength outside the range
820 nm to 946 nm, and those employing radiation other than that generated by the AOPDDR
itself. For sensing devices that employ radiation of wavelengths outside this range, this part
may be used as a guide. This part is relevant for AOPDDRs having a stated detection capability
in the range from 30 mm to 200 mm. AOPDDRs intended for use as trip device using wholebody
detection with normal approach to the detection zone and having a stated detection
capability not exceeding 200 mm shall meet the requirements of Clause A.12. AOPDDRs
intended for a direction of approach normal to the detection zone and having a stated detection
capability in the range from 30 mm to 70 mm shall meet the requirements of Clause A.13.
NOTE 2 According to ISO 13855 (EN 999), 6.3 foreseeable angles of approach greater than 30” should be
considered normal approach and foreseeable angles of approach less than 30” should be considered parallel
approach.
NOTE 3 According to ISO 13855 (EN 999), 6.2 when electro-sensitive protective equipment employing active optoelectronic
protective devices is used for direction of approach parallel to the detection zone the device should have
a detection capability in the range from 50 mm to 117 mm.This part may be relevant to applications other than those for the protection of persons, for
example, for the protection of machinery or products from mechanical damage. In those
applications, different requirements may be necessary, for example when the materials that
have to be recognized by the sensing function have different properties from those of persons
and their clothing.
This part does not deal with electromagnetic compatibility (EMC) emission requirements.
Opto-electronic devices that perform only one-dimensional spot-like distance measurements,
for example, proximity switches, are not covered by this part.