Installation and Commissioning

Safety SystemSystem DescriptionIf any of the dual switches in the safety circuit are opened, the circuit breaks, the motorcontactors drop out, and the robot is stopped by the brakes. If the safety circuit breaks,an interrupt call is sent directly from the panel unit to the robot computer to ensure thatthe cause of the interrupt is indicated.When the robot is stopped by a limit switch, it can be moved from this position by joggingit with the joystick while pressing the MOTORS ON button. The MOTORS ON button ismonitored and may be depressed for a maximum of 30 seconds.LEDs for ES, AS and GS are connected to the two safety circuits to enable quick locationof the position where the safety chain is broken. The LEDs are located on the upper part ofthe panel unit. Status indication is also available on the teach pendant display.5.2 MOTORS ON and MOTORS OFF modesThe principle task of the safety circuit is to ensure that the robot goes into MOTORSOFF mode as soon as any part of the chain is broken. The robot computer itself controlsthe last switches (ENABLE and MOTORS ON).In AUTO mode, you can switch the robot back on by pressing the MOTORS ON button onthe operator’s panel. If the circuit is OK, the robot computer then closes the MOTORS ONrelay to complete the circuit. When switching to MANUAL, the mode changes toMOTORS OFF, at which stage the robot computer also opens the MOTORS ON relay. Ifthe robot mode does not change to MOTORS OFF, the ENABLE chain will break and theENABLE relay is opened. The safety circuit can thus be broken in two places by the robotcomputer.In any of the MANUAL modes, you can start operating again by pressing the enablingdevice on the teach pendant. If the circuit is OK, the robot computer then closes theMOTORS ON relay to complete the circuit. The function of the safety circuit can bedescribed as a combination of mechanical switches and robot computer controlledrelays which are all continuously monitored by the robot computer.5.3 Safety stop signalsAccording to the safety standard ISO/DIS 11161 “Industrial automation systems -safety of integrated manufacturing systems - Basic requirements”, there are two categoriesof safety stops, category 0 and category 1, see below:The category 0 stop is to be used for safety analysis purposes, when the power supply to themotors must be switched off immediately, such as when a light curtain, used to protectagainst entry into the work cell, is passed. This uncontrolled motion stop may require specialrestart routines if the programmed path changes as a result of the stop.Category 1 is preferred for safety analysis purposes, if it is acceptable, such as whengates are used to protect against entry into the work cell. This controlled motion stoptakes place within the programmed path, which makes restarting easier.All the robot’s safety stops are category 0 stops as default.Safety stops of category 1 can be obtained by activating the soft stop (delayed stop)together with AS or GS. Activation is made by setting a parameter, see User’s Guide,section System Parameters, Topic: Controller.18 Product Manual