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machinery sequence control KS 98 application Description The operational economy of most plants is determined by the efficiency of its component devices and equipment, and is reduced considerably with sub-optimum load conditions. Therefore, it is advisable not to supply the required energy via a single large device, but to distribute it over several smaller units. Only the variations in actual demand are lined out by means of an individually controlled device. Depending on the situation, it might even be possible to do without this device, if the tolerance band of the controlled process (pressure, flow, etc.), is sufficiently wide. By means of a suitable sequence controller, the smaller units are switched on and off in a defined order, as required by the energy demand. This ensures that each device contributes to the total energy input with optimum efficiency. Typical application areas are: - Steam and hot-water boilers - Pumping plants (O2 supply in aeration tanks) - Compressors (compressed air supply) Cooling plants - Automatic filter plants - Switching of large heat loads (MW) - The advantages of reduced operating costs are obvious: - Optimum operating efficiency (low energy losses) - High availability - Selective switching of individual devices, e.g. for maintenance and repair, without interrupting plant operation - Cyclical permutation of device order ensures uniform operating time and wear of the devices The actual energy demand is determined by a PID controller, whose control output operates the individually-controlled device. |
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