APPLICATIONS OVERVIEW 13 14 APPLICATIONS OVERVIEW
Parallel Beam Muting Figure 3 For parallel-beam muting applications, see figure 3, select an 8000Series light curtain with a detection height to suit the specific project, plus an integrated mute sensor module, type (083-001).The mute sensors inside the muting module are positionedapproximately 420mm apart, mute sensor (M1) at one side of the main light curtain (LC1) and mute sensor (M2) at the other side of the light curtain as shown. To maintain the correct sequence of operation of the safety system the product or, palletised load passing through the light curtain should have a length greater than the distance between the two mute sensors (M1 and M2). For loads with a dimension less than the factory-set distance between mute beams it will be necessary to open the module housing and re-position the beams to suit the smaller product dimension.With the parallel-beam muting system it is a control system requirement that a ‘conveyor manufacturer run’ signal be provided, so as to maintain a high level of safety integrity. To enable correct operation of the safety system it is essential that the pre-programmed operating sequence be maintained. For a palletisedload travelling towards the machine the correct sequence is as follows:1.Conveyor run signal applied – ON2.Pallet load interrupts mute sensor (M1) – conveyor run ON3.Pallet load interrupts mute sensor (M1) and then the light curtain, (LC1)– conveyor run ON4.Pallet load interrupts mute sensor (M1), light curtain (LC1) and mutesensor (M2) – conveyor run ON 1.Pallet load clear of mute sensor (M1), while industrial still interrupting (LC1) and (M2) – conveyor run ON2.Pallet load clear of mute sensor (M1) and light curtain (LC1), while still interrupting mute sensor (M2) – conveyor run ON3.Pallet load clear of mute sensor (M1), light curtain (LC1) and mute sensor (M2) – conveyor run OFFA time limit of 0.2 to 7 seconds is applied between each beam ‘interruption’ until all three beams are blocked (Steps 2-4). At this point a 15 minute timer is activated. Providing (Step 5) is initiated within the timed period then the system programme will be satisfied. Between (Steps 5-7) the 0.2 to 7 second timer between each beam ‘clearance’ is re-instated. If the sequence of operation as described is not maintained throughout the entire pallet transfer the safety system will trip. The safety control system will allow pallet loads to stop in the mute sensors detection field. The 0.2 to 7 second timer used in the programmed sequence during pallet transfer will be put on ‘hold’ during periods when the conveyor stops. For example; the maximum time allowed between step 2 and step 3 would be seven seconds. However, should the conveyor stop during the 7 second period the timer will be put on ‘hold’ until the conveyor re-starts. As the conveyor re-starts the timer is automatically removed from the ‘hold’ condition and continues counting the 7 second period.Parallel-beam muting is usually selected for applications where there are large dimensional variations in both length and width between palletloads. 8000 SERIES8000 SERIES