The task of the M4000 Advanced, as is the case for other electro-sensitive protective equipment, is to detect persons accessing the hazardous area of a machine during operation and immediately switch it off. The active protective equipment can be temporarily bridged, however, with the help of additional sensor signals in order to allow material transport into or out of a palletizer, for example. During this so-called muting, the timing and logical sequence of signals from muting sensors, e.g. from photoelectric switches, is monitored and evaluated. At the same time, based on the structure of the muting system, it is necessary to ensure that nobody is able to enter a hazardous area. When a pallet passes, switching off of the machine by the M4000 Advanced is suppressed, but if a person passes, the entire conveyor process is subjected to an emergency stop.
New function, fewer sensors, more space available: Exit Monitoring
If muting stations are designed for material transport in both directions, they must be installed on both sides of the electro-sensitive protective equipment. Sometimes, however, the material transport to be protected only takes place in one direction, particularly in the case of machines in the end-of-line area of packaging plants: out of the palletizer, foil wrapper or strapping machine. For these applications, SICK has equipped the M4000 Advanced multiple light beam safety device with the ‘Exit Monitoring’ function. Whereby the muting sensors are located within the hazardous area. The goods to be transported out of the hazardous area may pass and the safety equipment is muted. If, however, the protective field of the M4000 Advanced is infringed without actuation of the muting sensors this must necessarily take place from the outside: the machine is brought to an immediate stop.
Exit Monitoring offers a range of advantages. The purchase, space requirement and installation of the previously required muting sensors are eliminated because only the muting sensors within the hazardous area need to be installed. This saves time and money. The exit area of the machine becomes more compact, and the risk of misalignment or tampering of the muting sensors installed there (through the handling of, for example, palletized goods) is eliminated. This ensures maximum availability of the safety technology – and thus the entire conveyor system. The timing of the complete muting cycle can be flexibly adapted by the M4000 Advanced. Depending on the safety requirements, the length of time that muting is maintained in the M4000 Advanced can be adjusted from 0.5 to 4 seconds. The set time starts automatically on release of the first muting signal and, on completion, ends the muting process. This allows optimum synchronization of the protective and muting function with the performance of the plant, and the resultant sequence of objects exiting the machine in the material flow. The protective equipment is immediately reactivated when the object has passed, independently of the set time, providing maximum safety.
Expanded diagnostic possibilities optimize availability
The three-level diagnostic system of the M4000 Advanced ensures greater availability of the plant, and transparency regarding the monitoring functions and muting processes. It is therefore possible to visualize faults occurring in the muting process rapidly and in detail. Immediate analysis of sensor signals and the material flow events in the muting zone ensures rapid and targeted fault correction. Delayed functional diagnosis is also possible: for this purpose, a data recorder can write signal sequences on the hard disk of a PC. In the case of a fault, the plant can thus become productive again as rapidly as possible and faults subsequently preemptively corrected. The last four system switch-offs are stored in the temporary memory of the M4000 Advanced. This process-related consideration allows the recognition of causes, the optimization of processes and, therefore, the proactive minimization of downtimes in the conveyor system.
The product series is rounded out with versions for restricted installation and cost conditions. The high resolution of the M4000 Advanced Curtain allows the reduction of safety distances, and thus the space requirement in and around the machine. The M4000 Advanced Active/Passive, with just one active side, halves the wiring effort and is therefore particularly economical. In compliance with the new EN 13855, if the 4-beam Active/Passive system is selected, the safety distance can be shortened or the lowest beam of the Active/Passive system can be located below the conveyor system, preventing the need for supplementary mechanical guards to prevent access by crawling below the system – both options offering cost benefits.