Use triple redundant transmitter to measure the important key parameters (such as the feed water flow, boiler drum water level, main steam flow rate, air volume, main steam pressure, the first level pressure, furnace pressure, and primary air pressure, etc.) and the control system automatically selects the  mid-value as the controlled variable. And if the difference between the data measured by the rest transmitters and the mid-value exceeds the range of setting in advance, alarm will be given. If the other two signals both exceed the limit and alarm is given, then the affected part in the control system is switched to manually operation. The operators may switch the Logic in three options to manually -operating on the keyboard, and select any one of the signals of the three transducers for automatically operating. Use dual redundant transducer to measure the secondary critical parameters, if the deviation of two signals beyond a certain scope, then alarm is given, and the affected control system will be switched to manually operating. If the signals between the two transducers are super bad, the control system will identify the comparison logic to the two signals of redundant transmitter. When one of the correct signals is detected, the operator will select the correct transmitter signal according to the prompt for automatic control again. When the redundant transmitter is used in the measurement of signal, if the signals are lost or the signals exceeds the practical possible scope of technical process, alarm shall be given, at the same time the affected part of the control system is switched from automatically operating to manually operating.