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APPENDIX
2. EAA: Effective Aperture Angle
Maximum angle of deviation from the optical alignment of the emitting element(s) and the receiving element(s) within
which the AOPD continues in normal operation.
4. ESPE: Electro-Sensitive Protective Equipment
Assembly of devices and/or components working together for protective tripping or presence sensing purposes and
comprising as a minimum
– a sensing device;
– controlling/monitoring devices;
– output signal switching devices and/or a safety-related data interface.
5. Light curtain
AOPD comprising an integrated assembly of one or more emitting element(s) and one or more receiving element(s)
forming a detection zone with a detection capability specified by the supplier. A light curtain with a large detection
capability is sometimes referred to as a light grid.
6. OSSD: Output Signal Switching Device
Component of the electro-sensitive protective equipment (ESPE) connected to the machine control system which, when
the sensing device is actuated during normal operation, responds by going to the OFF-state.
7. PL: Performance Level
Discrete level used to specify the ability of safety-related parts of control systems to perform a safety function under
foreseeable conditions.
8. Response time
Maximum time between the occurrence of the event leading to the actuation of the sensing device and the output
signal switching devices (OSSD) achieving the OFF-state.
9. SIL: Safety Integrity Level
Discrete level for specifying the safety integrity requirements of the safety functions to be allocated to the Electric /
Electronic /Programmable Electronic safety-related systems, where safety integrity level 4 has the highest level of
safety integrity and safety integrity level 1 has the lowest.
DEFINITIOnS
Device whose sensing function is performed by opto-electronic emitting and receiving elements detecting the
interruption of optical radiations generated, within the device, by an opaque object present in the specified detection
zone (or for a light beam device, on the axis of the light beam).
1. AOPD: Active Optoelectronic Protective Device
Means by which the electro-sensitive protective equipment (ESPE) monitors the state of control devices which are
external to the ESPE.
3. EDM: External Device Monitoring
