1、 Printed Copies are Uncontrolled Page 1 of 21 Standard Number w-EL4 Issue Date: 20011011 Global Manufacturing Standards Rev: LIGHT CURTAINS AND PRESENCE-SENSING DEVICES FOR MACHINE SAFEGUARDING 1.0 GENERAL For use in Europe, the qualification required for light curtains is that they be “CE“ marked (
2、 ) to indicate their construction complies with the relevant European Standards (EN) and that specific product certification has been given by a third party safety test agency (European Notified Body). Light curtains shall be provided with an EC Declaration of Conformity. For use in North America, t
3、he additional qualification required for light curtains is that they be UL Listed ( ) and CSA Certified ( ) and marked accordingly to certify compliance with the appropriate UL and CSA standards. 1.1 PURPOSE: This Standard provides functional, performance, and installation requirements for Safety Li
4、ght Curtains / Presence Sensing Devices (PSD) used for machine safeguarding, and for Presence Sensing Device Initiation (P.S.D.I.) to start a machine cycle. Notes: This Standard refers to Safety Light Curtains as a “Presence Sensing Device“ as defined in ANSI B11.19 and other standards. This is the
5、same device known as a “Presence Sensing Safeguarding Device (PSSD)“ as defined in ANSI/RIA R15.06, or as “Electro-Sensitive Protective Equipment (ESPE)“ as called in IEC 61496 standards. Section 3 “TECHNICAL REQUIREMENTS FOR PRESENCE SENSING DEVICE“ applies to manufacturers of Presence Sensing Devi
6、ces. Section 4 “APPLICATION REQUIREMENTS INSTALLATION/SYSTEM“ applies to the machine builder and/or safeguarding system installer. 1.1.1 EXCEPTION: P.S.D.I. shall not be used on mechanical or hydraulic power presses. 1.1.2 All P.S.D.I. applications shall be approved by Local plant and Corporate Safe
7、ty activities. (See Figure 5, available as Word processing document.) 1.1.3 The installation requirements of this Standard do not apply when the PSD is not being used to provide a safeguarding function. Printed Copies are Uncontrolled Page 2 of 21 Standard Number w-EL4 Issue Date: 20011011 Global Ma
8、nufacturing Standards Rev: 1.2 SCOPE: This Standard describes Safety Light Curtains (light curtains), which are “control reliable“ electronic safety devices actuated by sensing presence, and their associated interfaces. This Standard includes using such a device to either stop the machine, or to sta
9、rt the machine cycle automatically when the operator and other persons have left the protected area and the machine cycle can be safely initiated. In both cases the light curtain serves as a primary safeguarding device. Light curtains should not be confused with simple photoelectric sensors which ar
10、e designed for different applications and which can be adversely affected by various environmental conditions. Light curtains are built with self-checking electronics for as close to a “fail-safe“ operation as achievable. This means that (referring to ANSI B11.19 item 5.5.1): “When required by the p
11、erformance requirements of safeguarding, the device, system, or interface shall be designed, constructed, and installed such that a single component failure within the device, interface, or system shall not prevent normal stopping action from taking place but shall prevent a successive machine cycle
12、. This requirement does not apply to those components whose function does not affect the safe operation of the machine tool.“ NOTE: In the United States, selection and application of safeguarding systems is provided in the appropriate ANSI B11 Safety Standard for the particular type of machine tool
13、and shall take precedence over this standard. 1.3 DEFINITIONS: 1.3.1 LIGHT CURTAIN / PRESENCE-SENSING DEVICE: See ANSI B11.19 (2.39). 1.3.2 MINIMUM SAFETY DISTANCE: See ANSI B11.19 (2.50 the word “should“ as a recommendation. Printed Copies are Uncontrolled Page 3 of 21 Standard Number w-EL4 Issue D
14、ate: 20011011 Global Manufacturing Standards Rev: 2.0 REFERENCE STANDARDS: Whenever a specific standard is mentioned in this Standard, it is understood it will be the latest revision thereof, unless otherwise specified. 2.1 Ford Motor Company Global Manufacturing Standards w-EL3, w-EX1 (to be publis
15、hed). 2.2 INDUSTRY STANDARDS: 2.2.1 Code of Federal Regulations, Department of Labor, Occupational Safety and Health Administration (OSHA) 29 CFR 1910, particularly sections: 1910.211 (62) for Definitions, 1910.212 (a) (1) for machine guarding 1910.212 (a) (3) for point of operation guarding 1910.21
16、2 (a) (3) (ii) for General Requirements for All Machines 1910.217 (b) (13) for Control Reliability 1910.217 (h) (6)(xvii) for controls with internally stored programs 1910.217 (h) (9) (iv) for Minimum Object Sensitivity 1910.217 (h) (9) (v) for Safety Distance 2.2.2 American National Standards Insti
17、tute (ANSI) B.11.19 “Safeguarding when Referenced by other B11 Machine Tool Safety Standards,“ particularly, but not limited to sections: 1.1, 1.2, 1.3.1 see also IEC 60204-1 par. 9.4 for European requirements. 3.2.7 The Light Curtain shall be qualified for use in P.S.D.I. applications per OSHA 29 C
18、FR 1910.217. 3.3. ELECTRICAL: 3.3.1. ENVIRONMENTAL: The PSD shall operate properly in compliance with this Standard over a supply voltage range of 85 to 110 percent of the nominal 120 (or 230) VAC supply at 50/60 Hz, or the same percentage variations from a nominal 24 VDC for DC operated units. Volt
19、age variations may be the result of gradual and/or instantaneous supply variations. Additionally, the PSD shall be capable of operating in a temperature range of 0 degrees C (32 deg. F) to 60 degrees C (140 deg. F), and in a humidity range of 5 to 95 percent, non-condensing. PSD shall operate in bot
20、h ungrounded and grounded control circuits (120 VAC or 24 VDC as provided) without modification. 3.3.2 OUTPUT RELAYS: Relays shall have direct-drive (force-guided or captive) contacts to meet ANSI B11.19, Section 5.5, “Control Reliability.“ Off-the-shelf relays are preferred for ease of replacement,
21、 if the design permits replacement. Two redundant output relays shall be required. Contact Life and Bounce: PSD output relays shall have a minimum contact life of 10 million operations under stated full rated load. PSD shall be tested for contact bounce both before and after completion of all other
22、tests required in this Standard. Printed Copies are Uncontrolled Page 7 of 21 Standard Number w-EL4 Issue Date: 20011011 Global Manufacturing Standards Rev: 3.3.3 VIBRATION AND SHOCK TEST: PSD shall meet IEC 61496-1 section 5.4 “Mechanical influences“ requirements. 3.3.4 IMMUNITY TO INTERFERENCE AND
23、 ENVIRONMENTAL CONDITIONS: PSD shall not be affected by any of the following: Radio Frequency Interference (RFI) PSD shall be immune to RFI as required by the Industry Standards referenced in Section 2.2 and in accordance with the following practical field test: The RFI tests shall be conducted with
24、 a hand-held VHF transceiver with a rated power of five watts and fully charged batteries. There shall be no change in the state of the Light Curtain outputs when the transceiver is turned ON and OFF; also when the transceiver is keyed and its antenna held parallel, within 0.25 inches (6.3 mm), to a
25、ny part of the PSD enclosure. The antenna then will be moved parallel to and within 0.25 in. of the output cable or wiring connected to the PSD for a distance of four feet along the cable without change of output state. (2) Electromagnetic Interference (EMI). (3) Power Line Noise Interference, Volta
26、ge Variations, Transients. (4) Electrostatic Discharge - in accordance with IEC Publication 61000-4-1 at 2kV, 4kV, 8kV, and 15kV levels. (5) Strobe, Fluorescent, Sunlight, or Ambient Light Interference, per IEC 61496-2, section 5.4.6. (6) Application and Removal of Power: There shall be no change in
27、 the state of output from the PSD when the power is applied or removed. (8) Accumulation of dirt, oil, or water on or around the PSD. (9) Ferrous or non-ferrous metals on, or, within close proximity to the PSD. 3.3.5 RESPONSE TIME: The response time of the PSD shall not change due to degradation of
28、its light source or for any other reason. 3.3.6 ACTUATION INDICATORS: The PSD shall have lights readily visible to the operator that indicate its status. The recommended colors are: Green - PSD Outputs On (Actuated), Safe/Machine Ready. No part of the body of the operator, or any other person, or ob
29、ject is present in the active portion of the sensing field. Printed Copies are Uncontrolled Page 8 of 21 Standard Number w-EL4 Issue Date: 20011011 Global Manufacturing Standards Rev: Red - PSD Outputs Open. Part of the operators or another persons body is present in the “hazardous zone“ during a pa
30、rt of the machine cycle that is considered unsafe. If the red light has been activated, the PSD shall not go into a “green“ mode unless an intentional manual “reset“ is activated by the operator at the machine control panel. (see 4.1.4). Amber - Auxiliary Indicator (PSD specific). May be Caution/Cha
31、nge of machine condition/Alignment/ Reset required, the PSD is by-passed and/or deselected during a part of the machine cycle considered “safe“ or “non-hazardous“, e.g., the “dwell time“ in a hydraulic press process wherein the parts have been “pressed“ and are being cured. If the amber condition is
32、 not cleared before the initiation of the next machine cycle signal, the PSD shall go to a “red“ mode and stop any successive machine cycle operations. NOTE: This requirement may be waived if furnished in the “system.“ 3.4 Pressure Mats: Refer to Supplement A of this Standard (previously Ford Safety
33、 Technical Bulletin STB 114). 3.5 Perimeter Guarding “Optical Fences“ (applicable to Area Scanners): Shall, in addition to meeting all RELEVANT requirements of this Standard, comply with IEC 61496-3 for Area Scanners. 4.0 APPLICATION REQUIREMENTS - INSTALLATION/SYSTEM: 4.1.1 The system shall provide
34、 complete safety for the operator and/or any other person. 4.1.2 The system shall be of sufficient size to prevent the operator and/or other employees from having any part of their body in the danger zone by reasonably reaching around, over, or under the sensing field of the PSD. Supplemental safegu
35、arding shall be provided as required to prevent this entry described above. 4.1.3 The system shall prevent the operator from standing between the PSD sensing field and point of operation. 4.1.4 The system shall automatically monitor the external output circuit or Final Switching Devices (FSD) of the
36、 PSD every machine cycle and automatically switch to a safe condition if a single component failure is detected (i.e. control reliable). Printed Copies are Uncontrolled Page 9 of 21 Standard Number w-EL4 Issue Date: 20011011 Global Manufacturing Standards Rev: 4.1.5 The light curtain/PSD output shal
37、l be hard-wired into the machine control circuit and shall not be PLC logic-dependant only per Ford Standard w-EL3, Section 5. Contacts from force-guided interface relays connected to the light curtain/PSD or its interface module shall be used in pairs to directly interrupt safety-related controller
38、 outputs or other circuits. Refer to Section 5 of this Standard and the attached Figures. 4.1.6 To meet the intent of ANSI B11.19 Section 4.2.3.3.2, the suggested methods shown in the Figures at the end of this Standard should be followed. 4.2 MINIMUM SAFETY DISTANCE: 4.2.1 The machine builder shall
39、 calculate and furnish the safe distance from “point of operation“ to the location of the light curtain. This “Minimum Safety Distance“ shall take into consideration time for the machine to stop, the response time of the PSD, speed of operator, and mounting orientation of the PSD. Use guidelines in
40、ANSI B11.19, Section 4.2.3.3.5 or ANSI/RIA R15.06 section 10.4.3. NOTE: The appropriate ANSI B11 standard for a particular machine if it is more stringent - shall supersede this requirement. See also EN 999 “Safety of machinery the positioning of protective equipment in respect of approach speeds of
41、 parts of the human body.“ 4.2.1.1 Disclosure of Safety Distance Calculation: The MACHINE BUILDER shall provide a full disclosure of the “Minimum Safety Distance“ calculation on each 70Z*-controls drawing that depicts PSD unit(s). The calculation shall be performed in accordance with the formula pro
42、vided in the ANSI B11.1 and B11.19 standards and OSHA 1910.217 and/or EN 999 for machines used in Europe. The calculation shall be given and formatted as follows: (1) Provide a CHART inside a box border with the heading: MINIMUM SAFETY DISTANCE CALCULATION (see Figure 4). For minimum text height req
43、uirements refer to Ford w-EX6. (2) Include the complete Formula for the calculation just below the heading. Printed Copies are Uncontrolled Page 10 of 21 Standard Number w-EL4 Issue Date: 20011011 Global Manufacturing Standards Rev: (3) The Chart shown below the formula shall contain: (a) the indivi
44、dual Time value associated with each element of the safety stopping system, as well as the Depth Penetration Factor (Dpf) associated with the particular light curtain used; (b) the identifier for each component involved as shown on the 70Z*-drawings and mechanical drawings (e.g. LCR1/LCR2, I:01/12SO
45、L, Brake stopping time); (c) the individual distance (in inches) associated with each component; and (d) the total “Minimum Safety Distance“ (Ds) which shall be the sum of the individual distances. (4) The Brand and model of the PSD unit shall be included in a rectangle at the bottom of the box. 4.3
46、 BLANKING: 4.3.1 Blanking shall be permitted only by the approval of the Safety Engineer located at or responsible for the facility where the light curtain is used. 4.3.2 Blanking affects the Minimum Safety Distance, therefore, it shall be recalculated. 4.3.3 If Blanking is used, the PSD unit shall
47、have a cleary visible indication to the operator that the Blanking mode is activated. NOTE: This requirement may be waived if the control system provides such indication (see 4.3.6). 4.3.4 Blanking shall not affect the immunity of the PSD to the ambient light, shiny surfaces, etc. (see 3.2.1 and 3.2
48、.2). 4.3.5 Blanking shall not be used with P.S.D.I. applications. 4.3.6 If the PSD does not have an indicator to inform the operator that the PSD is in Blanking mode, the control system shall provide lights to indicate the blanking. Printed Copies are Uncontrolled Page 11 of 21 Standard Number w-EL4
49、 Issue Date: 20011011 Global Manufacturing Standards Rev: 5.0 APPLICATION EXAMPLES: 5.1 If there are no application issues with the equipment being guarded by the PSD that would prevent a complete shutdown when the PSD is interrupted, then the “Enable Signal“ of Circuit 1 or 2 may be used in the Emergency or Safety Stop circuit of the equipment. (See examples of in Figures 1 and 2). 5.2 If there are issues preventing a complete shutdown of the equipment when the PSD is interr
