Difference between redundancy and Triple redundancy module in PLC system.

[srinivasan]

See below specification and my understanding, if i am wrong, please correct me...

Specification-1: System shall have separate control and ESD PLC. both should get inputs from separate ESD and control instruments and equipments. Control and ESD PLC shall have redundancy module.

Understanding:

Control PLC architecture will be, Control instrument-IO module (2 numbers in parallel) -Processor (2 nos in Parallel)
ESD PLC architecture will be, ESD instrument- IO module ( 2 numbers in parallel) -Processor ( 2 nos in parallel ).

Specification-2: ESD system shall be Triple redundant Module with programmable Electronic system (PES)

Doubts:

i) It is that Control PLC will be redundancy module and separate control. No need of triple redundant module and interface with ESD module? if i am wrong, please correct me.

ii) What is the difference between PLC and PES. Are both different?

iii) Is it possible to obtain both spec in same system ? If possible, please explain?

thanks in advance...

 

[fmtjfw]

If you have two systems and they disagree, which one is right?

That's why a sailor (without a shortwave radio or GPS) would take one or three clocks with them on the voyage. With one you just have to believe it, with three you ignore the one with the odd readings. But with two, do you average the readings or just believe one (by flipping a coin perhaps).

Deep philosophical questions here!

 

[srinivasan]

If you have two systems and they disagree, which one is right?

That's why a sailor (without a shortwave radio or GPS) would take one or three clocks with them on the voyage. With one you just have to believe it, with three you ignore the one with the odd readings. But with two, do you average the readings or just believe one (by flipping a coin perhaps).

Deep philosophical questions here!

If i have to comply 3-2-0 voting system with ESD system, should i have dedicated instruments for all line or only for some (based on emergency position).. Also explain, If any body know clear about 3-2-0 voting system..