03-SafetySw 2 GuardLock 5/3/2010 2:19 PM Page 3-33 Safety Switches Guard Locking Switches Overview Overview Typical Sequence of Actions Guard locking switches are used to protect hazardous areas where 1. The operator requests to enter the hazardous area a danger is not immediately removed after a stop request. On many 2. A controlled or immediate stop of the machine is initiated machines removal of power of the motor or actuator will not 3. The machine is stopped: time delay expired or stop motion necessarily cause a reliable and immediate stopping of the detected dangerous motion. Typical applications are: high inertia rotating 4. The gate is unlocked by either energizing (Power to Release) or machines, fast rotating machines, and machines where high de-energizing (Power to Lock) the solenoid pressure needs to be released from pneumatic valves. 5. The operator opens the gate and works in the hazardous area Gates protected with guard locking switches are usually opened on 6. The operator exits the hazardous area and closes the gate exception basis. For example: to clear a jam or to regularly maintain 7. The operator restarts the machine the machine. This type of switch should not be used for frequent 8. The gate is locked by either de-energizing (Power to Release) or access during normal operation of the machine. energizing (Power to Lock) the solenoid Guard locking switches use a solenoid to activate a lock which 9. The machine returns to its normal speed blocks or releases the tongue from the switch. Manual Override Rockwell Automation offers two different types of guard locking Flexible Release switches: E-Stop Power to Lock Restart When power is applied to the solenoid, the tongue is locked in the switch. When power is removed, the lock is released allowing the tongue to be extracted from the switch. Power to Release When power is applied to the solenoid the lock is released allowing the tongue to be extracted from the switch. When power is E-Stop removed, the tongue is locked in the switch. Restart Restart Why Use Power to Lock or Power to Release Power to Lock Power to Release Guard Locking Gate Power is not applied to Switch When the power is the switch all the time, removed from the cell only when the door after a controlled stop, needs to be opened. Advantage the doors unlock Sudden lose of power allowing maintenance does not compromise personnel to go in easily. safety of personnel, as the doors stay closed. Sudden lose of power Rear Escape Loss of power will not will unlock the door unlock the door and allowing personnel to go In the situation where a person is still in the hazardous area, the Disadvantage maintenance personnel in the hazardous area door is locked and the machine restarts, the TLS guard locking will not be able to go and the machine may switch product family provides two options for the person to escape inside the cell. not be stopped. the hazard (in addition of an Emergency Stop located outside of the hazardous area): Different methodologies can help decrease the risk that the danger Option 1: Rear Escape (Not Latched) is removed before the operator has access to the hazardous area: A 40 mm push button is mounted on the back of the TLS and is Time based accessible from the inside of the cell. Pushing the rear escape push The risk assessment process and stop time measurement will button releases the lock mechanism inside the TLS guard locking determine the maximum time for the machine to stop from its switch allowing the door to be opened, the machine to stop and the normal speed of operation. This time defines the delay between the person to escape the hazardous area. request to open the gate and the authorization to access the zone by unlocking the gate by energizing (Power to Release) or de- Option 2: Flexible Release (Latched) energizing (Power to Lock) the solenoid. The flexible release push button accessory is designed to be This time delay can be implemented by using any of our time delay installed inside the hazardous area to provide a means of escape for units such as the MSR178 or MSR138 safety relay or by software in personnel who become trapped there. It provides remote access to one of our Safety PLC. the manual release mechanism within the TLS-GD2 switch in the event of an emergency situation. The flexible release can be retro- Stop motion fitted to existing TLS1-GD2 and TLS3-GD2 switches or installed Another methodology is to measure when the motion is stopped. along with a new switch. When the no-motion is detected, the lock is released to allow The unit is installed at an accessible height next to the guard door, personnel to enter the hazardous zone. inside the guarded area, while the TLS-GD2 can be mounted The CU2, CU3, or MSR57 safety relay will be used to detect the outside the guarded area. The flexible release is available with either motion is stopped. a 1 m (3.28 ft) or a 3 m (9.84 ft) cable. Safe speed conditions Pushing the black button on the flexible release, the movement of In some applications, the user may need access while the machine the cable activates the release mechanism within the switch, is running at a safe speed. The MSR57P used with encoder allowing the door to be opened, the machine to stop and the person technology can handle this application. It will verify the speed of the to escape the hazardous area. The flexible release is then reset motion and allow access only if the speed does not exceed a using the blue reset handle. preconfigured limit or otherwise the machine will enter a stop condition. Visit our website: www.ab.com/catalogs R 3-33 Publication S117-CA001A-EN-P 2-Opto-electronics Power Logic Operator 3-Interlock 1- General Interface Switches2-Opto-electronics General 1- 3-Interlock Operator Logic Power Switches Interface 03-SafetySw 2 GuardLock 5/3/2010 2:19 PM Page 3-34 Safety Switches Guard Locking Switches Overview Selection Guide 440G-MT TLS1-GD2 TLS2-GD2 TLS3-GD2 Atlas 5 Product Holding Force 1600 N (360 lb) 2000 N (450 lb) 5000 N (1124 lb) Housing Material Metal Plastic Metal Locking Mechanism Power to Release Power to Release Power to Lock Power to Release Power to Release Rear Escape and Rear Escape and Escape Release None None None Flexible Release Flexible Release Safety Contacts 2 N.C. 3 N.C. 2 N.C. 2 N.C. Aux Contacts 2 N.O. 1 N.O. 1 N.O. 1 N.O. Solenoid Monitoring Direct Drive 1 N.O. & 1 N.C. 2 N.C. 2 N.C. Typical Sequence of Actions and Contact Status Step 440G-MT TLS1 TLS2 TLS3 Atlas 5 Step 1Hazardous Area Protected Solenoid Power De-energized De-energized Energized De-energized De-energized Solenoid Feedback A/B Not Available Closed/Open Open/Closed Closed/Closed Closed/Closed Safety A/B Closed Closed Closed Closed Closed Aux A (/B ) Open Open Open Open Open/Open Step 2Access to Hazardous Area Solenoid Power Energized Energized De-energized Energized Energized Authorized Solenoid Feedback A/B Not Available Open/Closed Closed/Open Open/Open Open/Open Safety A/B Open Closed Closed Closed Closed Aux A (/B ) Closed Open Open Open Open/Closed Step 3Access Authorized AND Door Solenoid Power Energized Energized De-energized Energized Energized Open Solenoid Feedback A/B Not Available Open/Closed Closed/Open Open/Open Open/Open Safety A/B Open Open Open Open Open Aux A (/B ) Closed Closed Closed Closed Open/Closed Step 4Gate Ready to Be Locked Solenoid Power De-energized De-energized Energized De-energized De-energized Solenoid Feedback A/B Not Available Closed/Open Open/Closed Closed/Closed Closed/Closed Safety A/B Open Open Open Open Open Aux A (/B ) Closed Closed Closed Closed Closed/Open Step 5Door Locked and Hazardous Area Solenoid Power De-energized De-energized Energized De-energized De-energized Protected Solenoid Feedback A/B Not Available Closed/Open Open/Closed Closed/Closed Closed/Closed Safety A/B Closed Closed Closed Closed Closed Aux A (/B ) Open Open Open Open Open/Open Direct drive of the contacts from the solenoid forces the safety contact to open even if the door is closed. Aux B solenoid auxiliary contact is available only on the Atlas 5 safety switch. Visit our website: www.ab.com/catalog 3-34 R Publication S117-CA001A-EN-P