Muting Applications with the MSR300 Table of Contents

Transcription

1 Application Note Muting Applications with the MSR00 Table of Contents ) Purpose... ) References... ) Muting Input Module... ) Muting Sensors... 5) Muting Lamp Module... 6) Reset... 7) Saving the Configuration Settings into the Base Module... 8) Clearing a Jam... 9) Application: Material Handling with -Sensor Muting...5 a) General Considerations...5 b) Other similar applications...5 c) Schematic without Synchronous Detection...6 d) Schematic with Synchronous...7 e) Description of Operation...8 f) Bill of Materials...8 0) Application: Material Handling with -Sensor Muting and Additional Non-muted Area Scanner...9 a) General Considerations...9 b) Bill of Materials...9 c) Schematic...0 ) Application: -Sensor Muting with Automatic Reset for Forktruck and Manual Reset for Operator... a) General Considerations... b) Schematic... c) Description of Operation... d) Bill of Materials... ) Application: Material Handling with Four Sensor Muting... a) General Considerations... b) Schematic with No Timing Requirements...5 c) Description of Operation...6 d) Bill of Materials...6 ) Fault Considerations...6 ) Fault Exclusion...7 Page of 7 September 9, 006

2 MSR00 Muting Applications Rev D ) Purpose. The purpose of the application note is to describe the operation of the MSR00 in various applications where or sensors are used to mute the operation of a light curtain.. These are typical material handling application where an object is moving down a conveyor and must move into and back out of a protected hazard area. ) References. 9507, MSR00 Instruction Manual.. C5-CA00A-EN-P Sensor Catalog Preferred Availability Edition. A5-CA00A-EN-P Industrial Control Catalog. ISO 89-: 999, Safety of Machinery Safety-related parts of the control systems Part : General principles for design. Also published as EN ISO 89-: 999, Safety of Machinery Safety-related parts of the control systems Part : Validation 6. ANSI B.9, Performance Requirements for Safeguarding 7. RIA R5.06, Safety Performance Requirements for Robots and Robot Systems ) Muting Input Module. One of the MSR0 input modules must be configured for muting. This is done by adjusting the Group setting to 8. The Group 8 setting creates an interaction between the Group output module and the Groups and input module settings. Only the Group output module is muted, that is, the Group output remains energized when the corresponding muting input is active. Below is a summary of how the muting module creates the interaction between the modules.. When Group 8 is selected, the Group LEDs at the bottom of the module will be: -ON, -ON, and -Flashing. When the Input LED of the Group 8 muting input module is Green and a Group input (the light curtain in this application is obstructed) is deactivated, the H muting LED is on and the H terminals are energized, the Group output turns off, the Group output remains on, and the Group output remains on. Input Mute Signal Group inputs are muted.. When the Input LED of the Group 8 muting input module is Green, and a Group input (the scanner in this application detects an object) is deactivated, the H muting LED is on and the H terminals are energized, the Group output remains on, the Group output turns off, and the Group output remains on. Input Mute Signal Group inputs are muted 5. When both Input and Input of the Group 8 muting input module are Green, and a Group input (light curtain) is deactivated, the H and H muting LEDs are off and the H and H terminals are de-energized, the Group output turns off, the Group output remains on, and the Group output turns off. Inputs & Mute Signals Group and inputs are not muted 6. When both Input and Input of the Group 8 muting input module are Green, and a Group input (the scanner) is deactivated, the H and H muting LEDs are off and the H and H terminals are de-energized, Page of 7 September 9, 006

3 MSR00 Muting Applications Rev D the Group output remains on, the Group output turns off, and the Group output turns off. Inputs & Mute Signals Group and inputs are not muted 7. When both Input and Input LEDs of the Group 8 muting input module are Red, the H and H muting LEDs are off and the H and H terminals are de-energized. the Group output turns off when a Group input deactivates, the Group output turns off when a Group input deactivates, and the Group output turns off when either a Group or Group input deactivates. Inputs & Not Muted Group and inputs are not muted 8. Group 8 summary: With one input module set to Group 8, the muting operation operates like an Exclusive-OR operation. Muting Input Muting Input Group Output Muting Input Muting Input Group Output Muted 0 0 No 0 Yes 0 Yes No 9. Add a Group 9 input module, with only one input always active, to achieve an OR operation The MSR00 can then be used to mute the Group and inputs independently. Muting Input Muting Input Group Output Muted Muting Input Muting Input Group Output 0 0 No 0 Yes 0 Yes Yes ) Muting Sensors. Many different types of sensing technology can be used to create the muting, including photoelectric, inductive proximity, capacitive proximity, limit switches, and encoders. These sensors do not necessarily have to be safety rated. Photoelectric sensors are a very commonly used technology for muting.. In this application note, polarized retro-reflective sensors are used as they require less wiring than through-scan photoelectric sensors and they have a high tolerance to spurious reflections from stretch wrap packaging and shiny surfaces. 5) Muting Lamp Module. The muting lamp module provides monitored indication of the muting process. When the Group 8 muting input module LED is green, the muting lamp is turned on. If the current through the lamp is too low (<0mA) or too high (>00mA), the lamp module will automatically look to the reserve indicator. If the reserve is not functioning then all the outputs will turn off, when the light curtain or scanners are obstructed. The lamp must be replaced and the power to the MSR00 cycled to restart the MSR00.. The light curtain standard (IEC696-) as well as other standards (ANSI B.9, R5.06) require a muting lamp to indicate when the safeguarding device is muted. The MSR00 will operate Page of 7 September 9, 006

4 MSR00 Muting Applications Rev D without the muting lamp module. If the muting lamp module is not used, the auxiliary output of the Group 8 muting module (terminal S) must be connected to the machine control system, and the machine control system must control the muting lamp.. See the Industrial Control catalog for options on muting lamps. Control Tower Stack Lights do not have the desired current rating to be used as muting lamps. Pilot lights with incandescent bulbs can be used. LED s will not work as the current is below the 0mA limit. 6) Reset. The MSR00 must be set up for monitored reset of the Group output and automatic reset of the Group and outputs. This allows the system to automatically reset, when an object passes through the light curtain under proper muting, and requires manual intervention to restart the system if the muting process is violated.. The reset button should be blue in color with a normally open contact. See the Industrial Control Catalog for switch alternatives. 7) Saving the Configuration Settings into the Base Module. After setting the rotary switches on the MSR00, the base module must be taught the new configurations. This is accomplished by the following steps: a. Disconnect the input expansion modules from the base module. b. Insert the bus terminator plug into the left bus connector of the base module. c. Power up the Base Module. The "Status" LED changes from green to red and blinks to indicate that the Base Module is in configuration detection mode. The previous configuration is erased. d. Disconnect the power after at least one blink of the red LED. e. Remove the bus terminator plug from the base module, and then connect the required input expansion modules to the base module. f. Insert the bus terminator plug into the free bus connector of the last expansion module. g. Power up the system. After powering up, the current configuration is detected and stored by the Base Module in internal EEPROM. h. The MSR00 System then automatically steps into normal operating mode. 8) Clearing a Jam. Occasionally, the material will get stuck in the light curtain and sensors. To clear the material from the light curtain, a momentary key operated switch can be used to bypass the operation of the safety relay. This switch must be located in view of the muting operation to ensure that the bypass operation does not cause a hazard. The key must be used by authorized users and must not be left in the switch. Page of 7 September 9, 006

5 MSR00 Muting Applications Rev D 9) Application: Material Handling with -Sensor Muting a) General Considerations. This application allows material to move along a conveyor into a hazard area. Two photoelectric sensors are used to detect the approaching object and mute the light curtain as the object moves into the hazard area. See Figure for an overview of the application.. The sensors form an X pattern, where the crossing point lies in the plane formed by the light curtain. The X patterns for the muting sensors can be symmetric or asymmetric Symmetric Asymmetric. The size of the object must be large enough to block both sensors, while passing through the light curtain.. The order in which the sensors must be block is not relevant. The sensors work as a pair. 5. The material can move back and forth on the conveyor. Hazard Side Non-hazard Side Material Flow MSR9P MSR0P MSR0P MSR0P MSR0P Hazard Power Figure. -Sensor Application Layout b) Other similar applications. This sensor muting arrangement can also be applied to other applications: a. Overhead gantry applications, in which the light curtain protects an area where an object is lowered from overhead. The two muting sensors detect when the object reaches its low limit and mutes the light curtain, allowing the operator to access the object. b. Press applications, where the light curtain is muted on the upstroke of the press. The sensors detect the upward movement of the press, but not the downward movement. In this case, the sensor might be two limit switches being actuated by a rotating cam. If two light curtains need to be muted, each light curtain must be connected to separate input module, and each module should be set to the same Group switch setting. See the Muting Input Module section, below, for more details. Page 5 of 7 September 9, 006

6 MSR00 Muting Applications Rev D c) Schematic without Synchronous Detection. The order in which each sensor is block is not critical. The time difference between the blockage of Sensor and Sensor is not critical to the operation of the MSR00. +VDC Photoelectric Sensors Gnd Sensor Sensor Sender Receiver GuardShield Light Curtain Pink (OSSD) 6 5 Gray (OSSD) 7 Green A S S S S S S A S S MSR 9P A Lamp Module H MSR 0P Input Module Group 8 MSR 0P Input Module Group MSR0P Base Module G H H G H S S5 S6 S S5 S6 A TxD TxD Muting Lamp Primary (required) Reserve (optional) Must be no connection to Input for Muting Must jumper this unused input to V S RxD Reset Group Output Monitoring S S5 S Y0 Y Y Y Y MSR0P Group GND Y0 Y Y Y Y Groups, Automatic Reset Group Monitored Manual Reset K K L L L K K M Page 6 of 7 September 9, 006

7 MSR00 Muting Applications Rev D d) Schematic with Synchronous. This approach requires both sensors to be blocked within s of each other. The order in which the sensors are blocked is not important. +VDC Gnd Sensor DK Sensor DK Photoelectric Sensors GRU-90-QD 889N-F5AE-6F (N.O.) (N.C.) Grey (C) (N.O.) (N.C.) Grey (C) Sender Receiver GuardShield Light Curtain Pink (OSSD) 6 5 Gray (OSSD) 7 A S S S S S S A S S MSR 9P A Lamp Module H MSR 0P Input Module Group 8 Function MSR 0P Input Module Group MSR0P Base Module G H H G H S S5 S6 S S5 S6 A TxD TxD Muting Lamp Primary (required) Reserve (optional) Must be no connection to Input for Muting Must jumper unused inputs to V S RxD Reset Group Output Monitoring S S5 S Y0 Y Y Y Y MSR0P Group GND Y0 Y Y Y Y Groups, Automatic Reset Group Monitored Manual Reset K K Momentary Key Operated Switch LocatedinViewof Muting Operation L L L K K M Page 7 of 7 September 9, 006

8 MSR00 Muting Applications Rev D e) Description of Operation. For higher risk applications, use the second simultaneity feature of the MSR0 to add a timing element to the muting process. This helps reduce the possibility of defeating the muting by requiring the pair of sensors to be actuated within seconds of each other.. To utilize timing, the sensor must have voltage free contacts. For example, the 9000 Series sensor GRU-90-QD can be used. The MSR0P input module is set to Function and the sensor input wires are crossed: S goes to S instead of S and S goes to S instead of S. The sensor pairs must then detect the object within seconds of each other for successful muting.. When a timing fault occurs, the MSR0P input LEDs flashes red continuously. The MSR0 Status LED blinks repeatedly with two flashes. To clear this fault condition, both sensors must be cleared (not detecting any objects).. As the object approaches the light curtain, it is detected by Sensor. Sensor output goes high (V). 5. As it approaches closer, the object is detected by both Sensor and. Both sensor outputs are high (V). The Input LED of the muting module turns green. 6. The object passes through the light curtain. 7. The object passes by Sensor, which is now sensing its reflector. The input LED of the muting module turns red. 8. The light curtain is now active. 9. The object passes by Sensor, which is now sensing its reflector. a. f) Bill of Materials Partnumber Description Qty 0R-W9 MSR0P Base Module 0R-W8 MSR0P Input Module 0R-W7 MSR9P Muting Lamp Module 0R-W MSR0P Output Group 0L-PK600YD GuardShield Light Curtain, 0mm detection, 600mm height GRU-90-QD 9000 Series Photo Sensor, Polarized Retro, EM Relay Output, Mini QD (used for simultaneity timing) 9-05 Corner Cube reflector,.75mm (.5in), M5 screw 889D-FAC- Cordset pin Micro Quick Disconnect, m long 889D-F8AC- Cordset 8 pin Micro Quick Disconnect, m long 889N-F5AE-6F Cordset 5 pin, Mini Quick Disconnect, 6ft long (use with GRU- 800FM-F6 800F-MX0 800F-MP 90-QD) Reset button, metal, flush, blue, R N.O. contact block with latch, screw termination Metal enclosure, hole, M6/M0 knockout 0L-AMUTLPM Muting Lamp, V, W, incandescent, clear lens, m cable 606-XLP7E V Power Supply 7W Page 8 of 7 September 9, 006

9 MSR00 Muting Applications Rev D 0) Application: Material Handling with -Sensor Muting and Additional Non-muted Area Scanner a) General Considerations. Read the application for -sensor muting without synchronous detection for basic description of the muting operation.. An additional module, set to Group is required to add a non-muted device. In this example, a SafeZone Multizone scanner has been added as the non-muted device. Input of the Group 8 muting module must not connected to disable muting of Group input devices. Whenever an object enters the SafeZone detection area, the Group output turns off. b) Bill of Materials Partnumber Description Qty 0R-W9 MSR0P Base Module 0R-W8 MSR0P Input Module 0R-W7 MSR9P Muting Lamp Module 0R-W MSR0P Output Group 0L-PK600YD GuardShield Light Curtain, 0mm detection, 600mm height EF-PMPB-F RightSight Photo Sensor, Polarized Retro, PNP Output, m range, Micro QD 9-05 Corner Cube reflector,.75mm (.5in), M5 screw 889D-FAC- Cordset pin Micro Quick Disconnect, m long 889D-F8AC- Cordset 8 pin Micro Quick Disconnect, m long 800FM-F6 800F-MX0 800F-MP Reset button, metal, flush, blue, R N.O. contact block with latch, screw termination Metal enclosure, hole, M6/M0 knockout 0L-AMUTLPM Muting Lamp, V, W, incandescent, clear lens, m cable L-SFZNMZ l- CSFZNMZ-0 L-AMBSFZNMZ SafeZone Multizone with I/O Module 0m Prewired Conductor Cable with Memory Module Mounting Kit 606-XLP7E V Power Supply 7W Page 9 of 7 September 9, 006

10 MSR00 Muting Applications Rev D c) Schematic +VDC Photoelectric Sensors Gnd Sensor Sensor Sender Receiver GuardShield Light Curtain Pink (OSSD) 6 5 Gray (OSSD) 7 Green A S S S S S S S S S MSR 9P A Lamp Module H MSR 0P Input Module Group 8 MSR 0P Input Module Group MSR 0P Input Module Group G H H G H S S5 S6 S S5 S6 S S5 S6 Muting Lamp Primary (required) Reserve (optional) No connection to nd muting lamp as it is always disabled. Must be no connection to Input for Muting Must jumper these unused inputs to V Pink (OSSD) Gray (OSSD) SafeZone MultiZone (Connection for Single Zone) Reset A S S S S S5 S Y0 MSR0P Base Module A TxD TxD RxD GND Y0 Y Y Groups, Automatic Reset Group Monitored Manual Reset Y Y Group Output Monitoring Y Y Y MSR0P Group Y K K L L L K K M Page 0 of 7 September 9, 006

11 MSR00 Muting Applications Rev D ) Application: -Sensor Muting with Automatic Reset for Forktruck and Manual Reset for Operator a) General Considerations. In this example, a fork truck is the usual object that approaches a light curtain to load material onto a conveyor. Occasionally, an operator may also approach the conveyor to load materials or make adjustments to the materials already loaded. The system is setup to provide an automatic reset when the fork truck delivers material and manual reset if an operator breaks the light curtain. Operator Hard Guarding Muting Sensors Fork Truck Light Curtain Green - Powered - Muting Reset Conveyor. This application requires the detection of a forktruck, where the detection system does not detect an operator. In this application, two photoelectric sensors, without synchronous detection between the two sensors, are used to detect the Forktruck. Other sensor technologies can be used in place of the sensors. The important characteristic, based upon sensing technology or sensor placement, is that the sensors detect a forktruck and do not detect a person (operator).. IMPORTANT RISK CONSIDERATION Many standards require a separate, intentional act to re-initiate hazardous machine motion after clearing a safeguarding device. In this application example, the conveyor will be restarted as soon as the fork truck clears the light curtain. A risk assessment must take into consideration the case where the fork truck backs out of the light curtain but remains within the muting sensors. The forktruck driver, hopping off the forktruck, or a second operator attempts to make an adjustment to the pallet of material. In this case, the conveyor is powered because the light curtain is muted by the forktruck. A muting lamp must be located at the light curtain to warn individuals that the light curtain is muted. A second lamp should be provided to show that the conveyor is powered.. The conveyor power is driven by the Group output module. The Group output module is used to prevent the automatic reset of the conveyor motor when the muting action is not taking place. Page of 7 September 9, 006

12 MSR00 Muting Applications Rev D b) Schematic +VDC Photoelectric Sensors Gnd Sensor Sensor Sender Receiver GuardShield Light Curtain Pink (OSSD) 6 5 Gray (OSSD) 7 Green A S S S S S S A S S MSR 9P A Lamp Module H MSR 0P Input Module Group 8 MSR 0P Input Module Group MSR0P Base Module G H H G H S S5 S6 S S5 S6 A TxD TxD Muting Lamp Primary (required) Reserve (optional) Must be no connection to Input for Muting Must jumper unused input to V S RxD Reset S S5 S Y0 Y Y Y Y MSR0P Group MSR0P Group GND Y0 Y Y Y Y Groups, Automatic Reset Group Monitored Manual Reset K K Conveyor Powered L L L K K M Conveyor Motor Page of 7 September 9, 006

13 MSR00 Muting Applications Rev D c) Description of Operation. When the forktruck is detected by both sensors, the muting (Group 8) module becomes active and turns on the muting lamp. Output modules Group and remain energized and the conveyor is still powered. A green indicator is used to show that the conveyor motor is powered.. When the forktruck breaks the light curtain, the Group output module de-energizes and removes power from the conveyor motor. The Group output remains energized.. When the forktruck backs out of the light curtain, the Group output module re-energizes automatically and applies power to the conveyor motor.. When a person approaches the light curtain, the sensors are situated such that the person is not detected by the sensors. The light curtain is not muted. 5. When the person breaks the light curtain, both the Group and Group outputs de-energize and the conveyor motor turns off. 6. When the person clears the light curtain, both the Group and Group outputs remain denergized. 7. The operator presses the reset button to re-energize the Group and Group outputs which turn on the conveyor motor. d) Bill of Materials Partnumber Description Qty 0R-W9 MSR0P - Base Module 0R-W8 MSR0P -Input Module 0R-W7 MSR9P - Muting Lamp Module 0R-W MSR0P - Output Group 0R-W MSR0P - Output Group 0L-PK600YD GuardShield Light Curtain, 0mm detection, 600mm height GRU-900-QD 9000 Series Photo Sensor, Long Range Diffuse, NPN/PNP Output, Micro QD or Four photoelectric sensors, connected in parallel, may be required to continuously detect the forktruck while entering and leaving the light curtain Other sensor technologies may have to be substituted to detect the forktruck while ignoring people) 889D-FAC- Cordset pin Micro Quick Disconnect, m long 889D-F8AC- Cordset 8 pin Micro Quick Disconnect, m long 0L-AMUTLPM Muting Lamp, V, W, incandescent, clear lens, m cable 800FM-F6 800F-MX0 800F-MP Reset button, metal, flush, blue, R N.O. contact block with latch, screw termination Metal enclosure, hole, M6/M0 knockout 855T-BDN Conveyor Power Lamp, V, steady incandescent, green 855T-BPM0C Base, Aluminum 0cm height, black, with cap 606-XLP7E V Power Supply 7W Page of 7 September 9, 006

14 MSR00 Muting Applications Rev D ) Application: Material Handling with Four Sensor Muting a) General Considerations. This application allows material to move along a conveyor into a hazard area. Four photoelectric sensors are used to detect the approaching object and mute the light curtain as the object moves into the hazard area. See Figure for an overview of the application.. Two sensors are mounted on one side of the light curtain and the other two are mounted on the other side of the light curtain. The sensing line of sight goes directly across the conveyor. This approach tends to be easier to apply than -sensor muting when the shape and position of the object varies greatly.. The spacing of the sensors must be such that the object blocks all four sensors.. The order in which the sensors must be block is not relevant. The sensors work as a parallel set of pairs. 5. The material can move back and forth on the conveyor. Hazard Side Non-hazard Side Material Flow MSR9P MSR0P MSR0P MSR0P MSR0P Hazard Power Figure. -Sensor Application Layout Page of 7 September 9, 006

15 MSR00 Muting Applications Rev D b) Schematic with No Timing Requirements +VDC Gnd Photoelectric Sensors Sensor Sensor Sensor Sensor Sender Receiver GuardShield Light Curtain Pink (OSSD) 6 5 Gray (OSSD) 7 A S S S S S S A S S MSR 9P A Lamp Module H MSR 0P Input Module Group 8 MSR 0P Input Module Group MSR0P Base Module G H H G H S S5 S6 S S5 S6 A TxD TxD Muting Lamp Primary (required) Reserve (optional) Must be no connection to Input for Muting Jumper inputs to V to keep the Input LED green S RxD Reset Group Output Monitoring S S5 S Y0 Y Y Y Y MSR0P Group GND Y0 Y Y Y Y Groups, Automatic Reset Group Monitored Manual Reset K K L L L K K M Page 5 of 7 September 9, 006

16 MSR00 Muting Applications Rev D c) Description of Operation. As the object approaches the light curtain, it is detected by Sensor. Sensor output goes high (V).. As it approaches closer, the object is detected by both Sensor. Both sensor outputs are high (V). The Input LED of the muting module turns green. a. The sensors work in pairs. The order in which the two sensors and operate is not critical to the muting operation. Sensor can detect the object first, or both sensors can detect the object simultaneously. b. At this point the light curtain is muted. The object can pass through the light curtain without shutting down the hazard operation. c. If the sensors are connected to the MSR0 for simultaneity, Sensor must detect the object within seconds of Sensor.. The object passes through the light curtain, while also blocking Sensors and.. The object is detected by Sensor, and, and the light curtain. 5. The object is detected by Sensor,, and, and the light curtain. 6. The object passes by Sensor, which is now sensing its reflector. 7. The object passes by Sensor, which is now sensing its reflector. 8. The object passes through the light curtain. 9. The object passes by Sensor, which is now sensing its reflector. The input LED of the muting module turns red. Muting stops and the light curtain is now active. 0. The object passes by Sensor, which is now sensing its reflector. d) Bill of Materials Partnumber Description Qty 0R-W9 MSR0P Base Module 0R-W8 MSR0P Input Module 0R-W7 MSR9P Muting Lamp Module 0R-W MSR0P Output Group 0L-PK600YD GuardShield Light Curtain, 0mm detection, 600mm height EF-PMPB-F RightSight Photo Sensor, Polarized Retro, PNP Output, m range, Micro QD 9-05 Corner Cube reflector,.75mm (.5in), M5 screw 889D-FAC- Cordset pin Micro Quick Disconnect, m long 5 889D-F8AC- Cordset 8 pin Micro Quick Disconnect, m long 800FM-F6 800F-MX0 800F-MP Reset button, metal, flush, blue, R N.O. contact block with latch, screw termination Metal enclosure, hole, M6/M0 knockout 0L-AMUTLPM Muting Lamp, V, W, incandescent, clear lens, m cable 606-XLP7E V Power Supply 7W ) Fault Considerations. This sections identifies a sampling of faults. Additional potential faults must be identified during safety and risk assessment reviews. The machine designer and user must determine the likelihood of the faults leading to a hazardous situation and take risk reduction steps to mitigate the faults to an acceptable level.. A pair of sensors manually blocked. The sensors should be mounted in locations where they cannot be easily blocked by objects placed over the sensors by hand.. Extended Timing. Muting often uses a timed sequence or output duration. If the object gets stuck in a position where the light curtain is muted for an extended period of time, people may Page 6 of 7 September 9, 006

17 MSR00 Muting Applications Rev D take this opportunity to enter the hazard area while the hazard is still present. To add a timing element, sensor with one shot timing functions can be used to limit the muting time.. Crossfault on Sensor Inputs. Since non-safety rated proximity sensors with solid state outputs are used, the input module functions must be set to 6, which is for light curtains. Typically, light curtains perform crossfault detection, which is a short between Ch and Ch. In the picture below, one crossfault is a short from S to S. V Sensor Sensor Crossfault MSR 0P Input Module S S S Group 8 S5 S S6 5. Neither the MSR00 nor the sensors can detect this type of fault. Fortunately, the crossfault does not lead to the loss of the safety function. 6. A second fault, short from V power to S or S will cause the light curtain to be muted all the time. The machine designer and end user must determine the acceptability of the likelihood of this combination of events. Periodic verification of the muting and light curtain operation will detect this combination of faults. ) Fault Exclusion. Faults may be excluded per Section 7. of ISO 89- provided the guidelines in ISO89- Annex D are followed. Page 7 of 7 September 9, 006