1. The logic controller for the tripping protection system of steam turbine and boiler shall be redundant separately. 

2. The protection system of the boiler shall have independent I/O channels and the electrical isolation measures. 

3. The redundant I/O signals shall be introduced by different I/O module. 

4. The switch instrument and transducer of protection signal of triggering the unit to trip shall be set up separately, and when there is difficulty truly and it is required to share with other systems, the signal shall first enter into the protection system. 

5. The unit tripping command shall not be transmitted through the communication bus.