Problems caused by instrument failure leading to interlock actions
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Has your plant experienced interlock actions due to faulty instruments? Which interlock was it? Everyone is welcome to discuss
Yes. The main wind interlock is triggered as the measurement value drops due to water accumulation at the sensing point, and the two-out-of-three interlock also gets activated.
Occasionally there are~ it’s not important; you can bypass it, force it, or choose one of two options. For example, with the oxygen meter, a delay can also be applied! Many ways
This is the highest level of self-protection; most of its self-protection mechanisms have been activated
Bypassing is not allowed here; all self-protection mechanisms must be activated
The proportion of such problems occurring on-site must be quite high. These include the external environment, human factors, wiring issues, etc.
The instrument wire of the four-in-one furnace top pressure transmitter was damaged due to high temperatures, reaching full scale, which triggered the furnace shutdown interlock
There are interlocks for the fuel gas pressure of the furnace and for the pressure of the waste heat boiler; with only one interlock point, the likelihood of faulty readings due to instrument malfunction is higher.
Why do some people say that the two-out-of-two interlock design is not very safe? ?
Interlocks or two-out-of-three are more common, right?