How Siemens Safety Systems FMR Architecture Competing with TMR Systems!

Hi,

This is a wonderful example on many benefits of FMR over TMR systems
.

TMR systems are very costly bud rugged and are already proven. But I dont think siemens is far behind. Hence we are trying to educate the customers on the benefits of FMR.

Hope this presentation will help one and all.

regards,

H-H

 

unknown user

 

Great port H-H! Thank you. 

Hello Gunners ,

First I must thank you for sharing materials and information.

I'm not an ESD expert but I'm just interested in the subject and will share the few info. I have.

Couple of years ago I went with a local Siemens representative to an oil refinery where they wanted to replace a very old AUGUST TMR system (AUGUST is now belonging to ABB).
The whole system as you said was just in one cabinet but this one was very old.
I haven't seen modern TMR systems but I know that they got rid of that disadvantage.

At this time the Siemens representative was focusing on the philosophy of FMRsaying that FMR means that one CPU can access the 2 redundant modules at certain types of faults while in TMR system each CPU only talks to its assigned modules.

However and to the best of my knowledge, the FMR means that system can have 1oo1, 1oo2 and 2oo3 because the voting system is done in software (which is not a good thing by the way because it increases the scan cycle).


Now back to your presentation,
You said that TMR will force you to put all eggs in one basket so the CPUs and I/Os will be in the same cabinet.
As I told you it's not the same any more in some TMR systems.


Regardingthe burnt panels,
- I haven't seen mush ESD systems but all I've seen whether they were Siemens or any other, they were not distributed. I mean that all panels were in one location.

- I've seen burnt distributed panels before and I believe that no system on earth can survive partial burning.
When a distributed panel gets burnt, you lose the Profibusslavesnext to it.
So if you have a system for example with 50 panels and you lose panels 25 and 26, you lose panels from 27 till 50 and it doesn't take a small time to get the network running again.

- I've seenit inprocess control systems that could work while some slaves or panels are down but I believe that it's extremely hard and quite dangerous for an ESD system to keep working while some panels or slaves are down.
Maybe it works like this in aircraft carriers but I don't think it will work in oil and gas plants.


FMR vs. TMR & QMR
If I were you trying to convince an oil and gas customer that FMR (Siemens) is better than TMR, I would focus on,

1- any ESD or SIS system is based on a SIL level.

2- All electronic solutions in the market can never cross SIL3 and 99.9% if not 100% of plants are SIL3 or below (No SIL4).

3- Since any TMR is SIL3 and FMR is SIL3 as well then there's no need to spend much money on TMR(Usually they are much expensive).

I like the car example but I'm not good at telling it,
If your work is 60Km far from your home then,
Abicycle wouldn't be a good solution.
A Chinese car would break down after couple of weeks.
A Mercedes will definitely get you safe and calm and you wouldn't worry for breaking down before many years.
A Bugatti Veyron will do the same but you will never cross the 120 Km/h on your way to work although the Veyron can go up to 360 Km/h with 1000 HP.

That's how I really look at TMR and QMR (Quad. Modular Redundancy), They give you much more than what you need with much much more money.
But some fancycompanies like SAUDI ARAMCO wouldn't care for money. They willgo for the most expensive solutions.
(Anyhow I honestly like the Veyron no matter what. I mean the car not the TMR)



4- TMR systems are not easy to maintain and FMR is much easier.

5- Normally TMR systems are independent PLCs so it's not an easy thing to integrate them in DCS or process control systems while in Siemens you can easily do it.

6- Integration of safety matrix in PCS7.

7- You can even have both process control system and ESD (small systems) in one H-Controller.

I hope you will find the attacheddocument useful. It tellsabout the generations of ESD systems.


Best regards.

H-H